JP2013209279A - Hydrogen production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen production method which can convert an organic substance into hydrogen by efficiently reforming the organic substance by using a gas capable of being stably supplied, and can stably produce hydrogen at high efficiency with minimal production amounts of heavy fractions or carbonaceous materials, and furthermore which can be implemented by using relatively simple equipment, in a method for producing hydrogen by reforming an organic substance.SOLUTION: In producing hydrogen by reforming an organic substance, excess water vapor is added to an exhaust gas (g) containing carbon monoxide generated by a metallurgical furnace and a shift reaction is carried out, thereby constituting a mixed gas (g) containing hydrogen and carbon dioxide produced by the shift reaction, and water vapor not consumed by the shift reaction. The mixed gas (g) is brought into contact with the organic substance, bringing about a reforming reaction which converts the organic substance into lower molecules, and the product generated by the reforming reaction is steam reformed, thereby producing hydrogen.

Description

  The present invention relates to a method for producing hydrogen by reforming an organic substance such as plastic, and a method for operating a blast furnace or a steelworks using hydrogen produced by modifying an organic substance.

At present, most of waste plastic, oil-impregnated sludge, waste oil, etc. are incinerated. However, the incineration process has a high environmental load such as CO ₂ generation, and there is a problem of thermal damage of the incinerator, so that establishment of chemical recycling technology is required.
Among the chemical recycling technologies, technologies for reforming organic substances to convert them into hydrogen have been conventionally studied mainly on waste plastics. For example, the following proposals have been made.

Patent Document 1 discloses that a coke oven gas (COG) having a hydrogen concentration of 60 vol% or more, preferably 80 vol% or more and a temperature of 600 ° C. or more is reacted with an organic substance such as plastic to hydrocrack the organic substance with high efficiency. A method for gasifying and increasing the temperature of COG is disclosed.
Patent Document 2 discloses a method in which a plastic fluid contact catalyst (FCC) is used as a heat medium and catalyst, and plastic is decomposed and converted into liquid fuel at a temperature of 350 to 500 ° C.

Further, in Patent Document 3, when pyrolyzing RDF, wood, etc., the gas generated by pyrolysis is steam reformed, and the gas having a high hydrogen concentration by this steam reforming is circulated to the pyrolysis section to generate hydrogen. A method of performing pyrolysis in a gas atmosphere with a high concentration is disclosed.
Patent Document 4 discloses a method of producing hydrogen by thermally decomposing an organic substance in an oxygen-free state and steam reforming a hydrocarbon generated by the pyrolysis.
Patent Document 5 discloses a method for producing hydrogen by thermally decomposing a plastic in the presence of an oxidation catalyst and reacting water vapor with a carbide deposited on the catalyst surface by pyrolysis.

JP 2007-224206 A JP 2010-013657 A JP 2001-131560 A JP 2003-221203 A JP-A-5-330801

However, the above prior art has the following problems.
First, regarding Patent Document 1, since the hydrogen concentration in COG is 60 vol% or more is limited to the end of the dry distillation in the coal dry distillation process, in the method of Patent Document 1, the gas flow path is opened at the end of the dry distillation. It is necessary to switch and supply COG of 600 ° C. or more containing a large amount of dust to the plastic hydrocracking reactor. However, it is difficult to stably operate the flow path switching valve for a long time under such a severe condition, and in this sense, it can be said that the technique is poor in feasibility. Furthermore, for efficient gasification of plastics, it is necessary to continuously supply COG containing 60 vol% or more of hydrogen to the hydrocracking reactor. It is necessary to install a hydrogen concentration meter and a flow path switching valve, which increases equipment costs.

Moreover, although the method of patent document 2 advances catalytic cracking and aromatization by FCC catalyst addition, since it reacts by an inert gas flow, 13 mass% of heavy oil components and coke are produced | generated in total ( Example 1) is not a satisfactory level as a light fuel production technology.
Further, the gas generated by the method of Patent Document 3 is mainly H ₂ , CO, and CO ₂ , and the combustion heat is about 1800 kcal / Nm ³ that is slightly lower than that of the exhaust gas generated from the metallurgical furnace. The value is limited.
In the method of Patent Document 4, hydrocarbons are generated from organic substances such as plastics by a thermal decomposition method, and this is steam-reformed and converted to hydrogen. Therefore, hydrogen is produced from the carbonaceous material generated during the thermal decomposition. There is a problem that the hydrogen production efficiency is low. In addition, since the generated carbonaceous matter is extracted as a residue from the pyrolysis furnace together with the ash, waste that is difficult to recycle is increased.

Moreover, although the method of patent document 5 reacts water vapor | steam with the carbide | carbonized_material produced | generated by thermal decomposition and deposited on the catalyst surface, it is difficult to react all the carbide | carbonized_material deposited in the catalyst pore with water vapor | steam. In addition to the low hydrogen production efficiency, there is a problem that the catalyst is deactivated by the carbide remaining without reacting, resulting in high cost.
In general, hydrogen can be produced by reforming organic materials such as plastics in the presence of water vapor, but there are currently no known technologies for reforming organic materials such as plastics with high efficiency. is there.

  Accordingly, an object of the present invention is to efficiently reform an organic substance into a hydrogen by using a gas that can be stably supplied in a method for producing hydrogen by reforming an organic substance such as plastic. To provide a method for producing hydrogen that can be produced with a relatively simple facility, capable of producing hydrogen in a stable and highly efficient manner with a small amount of heavy components and carbonaceous matter. It is in.

As a result of repeated studies to solve the above problems, the present inventors have found that the following method is effective.
(A) By adding excess steam to the metallurgical furnace-generated exhaust gas containing carbon monoxide to cause a shift reaction, hydrogen and carbon dioxide generated by the shift reaction and steam not consumed in the shift reaction A mixed gas containing is obtained. Then, this mixed gas is used to reform the organic substance (lower molecular weight), and the product (hydrocarbon) generated by this reforming is steam reformed (the hydrocarbon is converted into hydrogen and carbon monoxide). ).
(A) Preferably, in the method (A) above, after the product produced by the reforming reaction of the organic substance is steam reformed, a shift reaction (converting carbon monoxide into hydrogen) is further performed. Alternatively, in the method (a), a gas product (light hydrocarbon) is separated from a product generated by the reforming reaction of the organic substance, the gas product is steam reformed, and then a shift reaction (one Carbon dioxide is converted to hydrogen).
It was also found that the composition of the mixed gas (shift reaction product gas) for modifying the organic substance has a suitable range.

The present invention has been made on the basis of such findings and has the following gist.
[1] In producing hydrogen by reforming an organic substance, a shift reaction is performed by adding excess water vapor to an exhaust gas (g ₀ ) containing carbon monoxide generated in a metallurgical furnace to cause a shift reaction. The mixed gas (g) containing hydrogen and carbon dioxide gas generated in step 1 and water vapor not consumed in the shift reaction is brought into contact with the organic substance to reform the organic substance and reduce the amount. A method for producing hydrogen, wherein a hydrogenation is generated by causing a molecularization reaction and steam reforming a product generated by the reforming reaction.
[2] The method for producing hydrogen according to [1], wherein the mixed gas (g) has a water vapor concentration of 5 to 70 vol%.

[3] The method for producing hydrogen according to [1] or [2], wherein the mixed gas (g) has a hydrogen concentration of 5 vol% or more and a carbon dioxide gas concentration of 5 vol% or more.
[4] In the production method of any one of [1] to [3], the exhaust gas (g ₀ ) has a carbon monoxide concentration of 25 to 80 vol%, a carbon dioxide concentration of 10 to 25 vol%, and a nitrogen concentration of 10 to 10. 30 vol% and hydrogen concentration are 0-20 vol%, The manufacturing method of hydrogen characterized by the above-mentioned.
[5] In the production method according to any one of [1] to [4] above, the product generated by the reforming reaction of the organic substance is steam reformed, and then hydrogen is generated by further performing a shift reaction. A process for producing hydrogen, characterized in that

[6] The method for producing hydrogen according to the above [5], wherein after the gas generated by the steam reforming is cooled, the shift reaction is performed by adding steam or / and water.
[7] The method according to any one of [1] to [6] above, wherein a gas product is separated from a product generated by a reforming reaction of an organic substance, and the gas product is steam-reformed. A method for producing hydrogen.
[8] The method according to any one of [1] to [6] above, wherein a liquid product is separated from a product generated by a reforming reaction of an organic substance, and the liquid product is steam-reformed. A method for producing hydrogen.

[9] In the production method according to any one of [1] to [8] above, the organic material reforming reaction and the steam reforming of the product generated by the reforming reaction are performed in separate reactors, A method for producing hydrogen, wherein steam reforming is performed by adding steam to a product generated by a reforming reaction of a substance.
[10] In the production method of any one of [1] to [6] above, using a mixed gas (g) containing or added with steam necessary for steam reforming, A method for producing hydrogen, characterized in that steam reforming of a product produced by the reforming reaction is performed in one reactor.
[11] In the production method according to any one of [1] to [10], the mixed gas (g) has a water vapor concentration of 20 to 70 vol%, a hydrogen concentration of 10 to 40 vol%, and a carbon dioxide gas concentration of 10 to 40 vol%. A method for producing hydrogen, wherein

[12] In the production method of any one of [1] to [11] above, the gas composition of the mixed gas (g) is adjusted by adjusting an excess ratio of water vapor added excessively with respect to the exhaust gas (g ₀ ). A method for producing hydrogen, characterized by controlling.
[13] In the production method according to any one of [1] to [12] above, the mixed gas (g) is brought into contact with the organic substance in the fluidized bed, thereby causing a reaction that modifies the organic substance to reduce the molecular weight. A method for producing hydrogen, characterized by comprising:
[14] In the production method of [13] above, at least a powder (f) having a true density of 4 to 8 g / cm ³ and containing at least one selected from Fe, Ni, and Cr is fluidized. A method for producing hydrogen, comprising using a fluidized bed as a part of a medium.
[15] The method for producing hydrogen according to [14], wherein at least a part of the granular material (f) is iron-containing dust generated in a steel making process.

[16] In the production method of [14] or [15] above, the gas (g _p ) discharged from the fluidized bed is passed through a dust collector to collect the fluid medium contained in the gas (g _p ). A method for producing hydrogen, wherein the collected fluid medium is circulated in a fluidized bed.
[17] In the manufacturing method according to any one of [1] to [16], the exhaust gas (g ₀ ) separates at least a part of nitrogen from the exhaust gas containing carbon monoxide and nitrogen generated in the metallurgical furnace. A method for producing hydrogen, characterized in that the exhaust gas has an increased carbon monoxide concentration.
[18] In the production method according to any one of [1] to [17] above, heat is recovered from the gas generated by steam reforming and / or the gas generated by the shift reaction after steam reforming, and the recovered heat Is used as a heat source for producing steam for steam reforming and / or steam for shift reaction.

[19] In the production method according to any one of [1] to [18] above, off-gas and / or organic material reforming after separating hydrogen from gas obtained by steam reforming or subsequent shift reaction A method for producing hydrogen, characterized in that a part of the gas product produced by the method is used as a heat source fuel for a steam reforming reactor.
[20] The method according to any one of [1] to [19], wherein the organic substance to be modified is at least one selected from plastic, oil-containing sludge, waste oil, and biomass. A method for producing hydrogen.
[21] A method for operating a blast furnace, wherein hydrogen obtained by the production method according to any one of [1] to [20] is blown into a blast furnace.
[22] An iron mill characterized in that hydrogen obtained by the production method of any one of [1] to [20] is used as one or more of a raw material gas, a reducing agent, and a fuel in the iron mill. Operating method.

According to the method for producing hydrogen according to the present invention, in producing hydrogen by reforming an organic substance such as plastic, hydrogen is produced by efficiently reforming the organic substance using a gas that can be stably supplied. In addition, it is possible to produce hydrogen in a stable and highly efficient manner while producing a small amount of heavy components and carbonaceous matter. Also, with regard to the implementation equipment, there is no need for special measuring instruments or flow path switching valves, and the organic substance can be reformed even at a relatively low reaction temperature. it can.
In addition, as a mixed gas for reforming organic substances, it is particularly efficient to use a mixed gas generated by adding excess water vapor to a metallurgical furnace-generated exhaust gas containing carbon monoxide to cause a shift reaction. Thus, hydrogen can be produced at low cost. For this reason, a large amount of hydrogen can be produced at low cost from an organic substance such as plastic. In addition, since CO ₂ generated by the shift reaction for obtaining the mixed gas for organic substance modification is changed to CO by the carbon dioxide reforming reaction during reforming of the organic substance, chemical recycling of the organic substance is performed by CO _2. It becomes possible to carry out without increasing the generation amount.
Further, according to the operation method of the blast furnace or steel plant according to the invention, a large amount of raw material gas in the steelmaking facilities of the blast furnace hydrogen which is inexpensive to manufacture, reducing agent, since that can be used as such as a fuel, to reduce CO ₂ emissions Can contribute.

In the shift reaction performed by adding water vapor to the converter gas, a graph showing the relationship between the amount of water vapor added and the composition of the gas after the shift reaction (calculated equilibrium composition at a temperature of 430 ° C.) Explanatory drawing which shows typically one Embodiment of the manufacturing facility for manufacturing hydrogen by this invention method Explanatory drawing which shows typically other embodiment of the manufacturing facility for manufacturing hydrogen by this invention method Explanatory drawing which shows typically one Embodiment of the equipment for performing the shift reaction of metallurgical furnace generation | occurrence | production waste gas, and the modification | reformation which makes an organic substance low molecular weight in this invention method Explanatory drawing which shows typically one Embodiment of the equipment which carries out steam reforming and shift reaction of the gas product obtained by modification | reformation of an organic substance in this invention method Explanatory drawing which shows typically one Embodiment of the equipment for performing the modification | reformation which makes an organic substance low molecular weight in this invention method In [Example 2], the graph which shows the relationship between the water vapor | steam density | concentration of shift reaction product gas, and the gasification rate and liquefaction rate in the modification | reformation (low molecularization) of polyethylene In [Example 2], the graph which shows the relationship between the water vapor | steam density | concentration of shift reaction product gas, and LHV of the gas product and liquid product obtained by the modification | reformation (low molecular weight reduction) of polyethylene. In [Example 2], the graph which shows the relationship between the water vapor | steam density | concentration of shift reaction product gas, and the polyethylene decomposition rate in the modification | reformation (low molecular weight) of polyethylene In [Example 2], the graph which shows the relationship between the carbon dioxide gas concentration of shift reaction product gas, and the hydrogen concentration of the gas product obtained by the modification | reformation (low molecular weight reduction) of polyethylene In [Example 2], the graph which shows the relationship between the hydrogen concentration of shift reaction product gas, and the carbon dioxide gas concentration of the gas product obtained by the modification | reformation (low molecular weight) of polyethylene

In the method for producing hydrogen of the present invention, in producing hydrogen by reforming an organic substance, exhaust gas containing carbon monoxide (g ₀ ) generated in a metallurgical furnace (hereinafter referred to as “metallurgical furnace generated exhaust gas”). This is a mixed gas containing hydrogen and carbon dioxide generated by the shift reaction and water vapor not consumed in the shift reaction. (G) (hereinafter sometimes referred to as “shift reaction product gas”) is brought into contact with an organic substance to cause a reforming reaction of the organic substance (lower molecular weight), and the product ( Hydrocarbon) is steam reformed to generate hydrogen. Preferably, in the above method, the product generated by the reforming reaction of the organic substance is subjected to steam reforming, and then a shift reaction is further performed to generate hydrogen through a series of these steps.
In the above method, the gas product (light hydrocarbon) or liquid product is separated from the product generated by the reforming reaction of the organic substance, and the gas product (light hydrocarbon) or liquid product is steamed. It can be modified.

Generally, the decomposition gasification reaction of plastics or the like is performed under severe conditions of several MPa and 1000 ° C. In addition, the liquefaction to obtain a liquid product is a mild reaction condition of about 300 to 400 ° C. at normal pressure, but because it is liquefied by a thermal decomposition reaction, it essentially lacks hydrogen, and heavy substances such as carbonaceous matter. A quality product is produced. On the other hand, in the method of the present invention, for the reasons described later, the reforming (lower molecular weight) of an organic substance is efficiently promoted under a relatively mild reaction condition of normal pressure and about 600 to 1000 ° C. As a result, high efficiency is achieved. In addition, hydrogen is produced, and no heavy or carbonaceous matter is observed.
In general, it is known that a high molecular weight organic substance such as plastic begins to thermally decompose when heated at a temperature of 300 to 400 ° C. or higher, but at this time, it becomes lighter and heavier. On the other hand, if hydrogen is present during thermal decomposition, the hydrogenolysis reaction and / or hydrogenation reaction of the organic substance proceeds, which is effective for suppressing the increase in weight and reducing the weight (reducing the molecular weight). However, when only hydrogen is present alone, there is a problem that high temperature is required for hydrocracking and hydrogen consumption is increased.

On the other hand, when water vapor or carbon dioxide gas is present, carbon atoms contained in the organic substance are oxidized by oxygen in H ₂ O or CO ₂ molecules to generate carbon monoxide and hydrogen. This means that the carbon chain of the organic substance is shortened, that is, the organic substance is decomposed, and the low molecular weight and the suppression of carbonaceous production can be achieved with a small hydrogen addition amount. Furthermore, steam reforming and carbon dioxide reforming are characterized in that the reaction temperature decreases as the carbon chain of the organic molecule to be modified becomes longer. In the method of the present invention, the reforming of organic substances (lower molecular weight) is promoted efficiently even at a relatively low reaction temperature, the amount of hydrogen consumption is small, and the generation of heavy components and carbonaceous matter is hardly observed. , By reforming organic substances (lower molecular weight) using the above mixed gas (g) in which steam, carbon dioxide and hydrogen coexist, hydrogenation (hydrogen addition reaction), hydrocracking, steam reforming, This is probably because the four reactions of carbon dioxide reforming proceed simultaneously. Each reaction formula of hydrogenation, hydrocracking, steam reforming and carbon dioxide reforming is shown below. In the reaction formula shown below, for simplicity, an organic substance used in the present invention a hydrocarbon (C _m H _n).
Hydrogenation: C _m H _n + H ₂ → C _m H _{n + 2}
Hydrocracking: C _m H _n + H ₂ → C _p H _q + C _r H _s (m = p + r, n + 2 = q + s)
Steam reforming: C _m H _n + H ₂ O → C _m-1 H _n-2 + CO + 2H ₂
Carbon dioxide reforming: C _m H _n + CO ₂ → C _m-1 H _n-2 + 2CO + H ₂
However, hydrogenation includes the following methanation reactions of CO and CO ₂ .
CO + 3H ₂ → CH ₄ + H ₂ O
CO ₂ + 4H ₂
→ CH ₄ + 2H ₂ O
The above hydrogenation and hydrocracking also proceed with H ₂ generated by steam reforming or carbon dioxide reforming.

That is, the production method of the present invention includes the hydrogenolysis reaction and / or hydrogenation reaction of an organic substance with hydrogen, as well as the oxidation of carbon atoms in the organic substance by oxygen atoms contained in water vapor or carbon dioxide, that is, the organic substance As a result, it is considered that the reforming reaction of organic substances such as plastics efficiently proceeds under relatively mild reaction conditions of about 600 to 1000 ° C. under normal pressure. It is done.
However, in the present invention, oxygen molecules (oxygen gas, liquid oxygen) and various peroxides are not used as the oxidizing agent. This is because the presence of such a strong oxidizing agent causes explosion and combustion, and the organic substance cannot be stably modified. Explosion and combustion can be avoided by setting the O ₂ concentration to be lower than the lower limit of the combustion range. However, since complete oxidation to CO ₂ proceeds, the cold gas efficiency is lowered, which is not preferable.
As the hydrogenation reaction, not only hydrogen addition reaction to hydrocarbon species, but also hydrogen addition reaction to CO or CO ₂ that produces light hydrocarbons such as methane as shown in the above reaction formula. This is suggested by the analysis result of the gas product. In the description of the present invention, for the sake of simplicity, the hydrogenation reaction to CO or CO ₂ is simply described as hydrogenation (or hydrogenation reaction) without being distinguished from the hydrogenation reaction to hydrocarbon species.

Hereinafter, details and preferred conditions of the present invention will be described.
In the method of the present invention, first, hydrogen and carbon dioxide generated by the shift reaction are performed by adding excess water vapor to the exhaust gas (g ₀ ) containing carbon monoxide generated in the metallurgical furnace, and performing the shift reaction, A mixed gas (g) containing water vapor not consumed in the shift reaction is obtained. This mixed gas (g) is a mixed gas containing water vapor, carbon dioxide gas, and hydrogen.
Further, the exhaust gas (g ₀ ) may be an exhaust gas in which the concentration of carbon monoxide is increased by separating at least a part of nitrogen from the exhaust gas containing carbon monoxide and nitrogen generated in the metallurgical furnace.
In the method of the present invention, adding excess water vapor to the exhaust gas (g ₀ ) means adding water vapor so that excess water vapor that is not consumed in the shift reaction remains in the mixed gas (g). That is, the excess water vapor means that it is excessive with respect to the stoichiometry of the shift reaction to obtain the mixed gas (g). Therefore, adding excess water vapor means that in the exhaust gas (g ₀ ) It means that more than equimolar amount of water vapor is added to CO.

For example, the exhaust gas generated from a metallurgical furnace such as a converter usually contains about 25 to 80 vol% of CO. Therefore, when water vapor is added thereto, H ₂ and CO ₂ are generated by the following shift reaction (1).
CO + H ₂ O → H ₂ + CO ₂ (1)
In the method of the present invention, since excess water vapor is added to the exhaust gas (g ₀ ), the mixed gas (g) after the shift reaction includes H ₂ , CO ₂ generated by the shift reaction, and H ₂ O of excess addition. Will be included. This shift reaction product gas (g) can be used as it is or after further addition of water vapor as a gas for organic substance reforming (supplied to the reforming reactor). In the reforming of organic substances (reduction in molecular weight) by this shift reaction product gas (g), it is considered that four reactions of hydrogenation, hydrocracking, steam reforming and carbon dioxide reforming by each gas component proceed simultaneously. It is done.

In the method of the present invention, the concentration of water vapor, hydrogen, and carbon dioxide in the gas is controlled by appropriately controlling the excess ratio of water vapor added excessively to the exhaust gas (g ₀ ) and the reaction rate of the shift reaction, It can be set as a mixed gas (g) used for organic substance modification. However, as described later, the composition of typical metallurgical furnace generated exhaust _{gas, CO: 25~80vol%, CO 2} : 10~25vol%, N 2: 10~30vol%, H 2: about 0～20Vol% in In addition, the general composition of the metallurgical furnace-generated exhaust gas stored in a gas holder (for example, a general gas holder used in steelworks) is CO: 50 to 70 vol%, CO2: 10 to ₂₀ vol% , N ₂ : 10 to ₂₀ vol%, H ₂ : 0 to 5 vol% (including saturated steam in addition), generally, it is not necessary to perform the reaction rate control of the shift reaction, and the excess ratio of water vapor is adjusted. By simply doing this, each concentration of water vapor, hydrogen, and carbon dioxide in the mixed gas (g) can be controlled to a desired level.
The reaction rate of the shift reaction can be controlled by adjusting the residence time in the shift reactor. For example, in order to shorten the residence time, a method in which the shift reactor length is reduced or the catalyst charge amount is reduced is generally used. In this case, the shift reactor length and the catalyst charge amount are almost until equilibrium. What is necessary is just to set it as about 1 / 2-1 / 4 in the case of advancing reaction.

As an example, converter gas of 100 kmol / h (= 2240 Nm ³ / h) having a composition of CO: 65 vol%, CO ₂ : 15 vol%, N ₂ : 18 vol%, H ₂ : 1 vol%, H ₂ O: 1 vol% In the case of performing the shift reaction by changing the amount of water vapor added from 60 kmol / h (= 1340 Nm ³ / h) to 540 kmol / h (= 1100 Nm ³ / h), the amount of water vapor added and the composition of the gas after the shift reaction ( The calculated equilibrium composition at a temperature of 430 ° C. is shown in FIG. According to this, it can be seen that the concentration of water vapor, hydrogen, and carbon dioxide in the mixed gas (g) can be controlled only by adjusting the amount of water vapor added, and a preferable gas composition as described later can be obtained. In addition, it is well known that the shift reaction usually proceeds to almost equilibrium.
Here, it is obvious that a mixed gas equivalent to the mixed gas (g) of the present invention can be obtained by mixing each gas component (pure gas) constituting the mixed gas (g). Pure gas is usually expensive and is not considered to be a reasonable method for industrially producing hydrogen. As in the present invention, it is particularly advantageous for efficient hydrogen production to obtain a mixed gas (g) using an exhaust gas generated from a metallurgical furnace containing carbon monoxide. Since it is cost, it is preferable.

Hereinafter, conditions for obtaining the mixed gas (g), a preferred composition of the mixed gas (g), and the like will be described.
The reason why the metallurgical furnace-generated exhaust gas is used as the exhaust gas (g ₀ ) for the shift reaction as in the present invention is that the metallurgical furnace-generated exhaust gas contains carbon monoxide at a relatively high concentration and the concentration of unnecessary nitrogen is low. Because. As the metallurgical furnace-generated exhaust gas (g ₀ ) containing carbon monoxide, any one can be used. The most representative is the converter gas generated from the converter where the decarburization process of the steel manufacturing process is performed, but other than that, for example, shaft furnaces such as blast furnaces and scrap melting furnaces, hot metal pretreatment furnaces Exhaust gas generated from a smelting reduction furnace or the like can be exemplified, and one or two or more of these mixed gases can be used.
The secondary combustion rate (CO ₂ / (CO + CO ₂ ) × 100), which is the rate at which carbon monoxide produced in the metallurgical process is further oxidized to produce carbon dioxide, is generally only about 10 to 50%. Moreover, although hydrogen and nitrogen are contained in the metallurgical furnace generated exhaust gas, the H ₂ concentration varies depending on the metallurgical process and is about 0 to 20 vol%. Nitrogen is supplied for in-furnace agitation and flue safety, and the concentration in the exhaust gas (g ₀ ) is usually about 10 to 30 vol%.

From the above points, the composition of general metallurgical furnace generated exhaust gas is generally in the following range.
CO: 80-25 vol% (equivalent to 10-50% secondary combustion rate)
CO _2: 10~25vol% (corresponding to the secondary combustion rate 10-50%)
N _2: 10~30vol%
H2: 0 to ₂₀ vol%
Although carbon monoxide is required for the shift reaction, there is no particular problem with the composition of the exhaust gas (g ₀ ) as long as the gas composition is in the above range. Here, nitrogen does not contribute at all to the chemical reactions (shift reaction, hydrogenation, hydrocracking, steam reforming, carbon dioxide reforming) that occur in the method of the present invention, while diluting the gas product produced. The lower heating value (hereinafter referred to as “LHV”) is reduced. In particular, when the nitrogen concentration exceeds 50 vol%, the LHV of the gas product is significantly reduced and the shift reaction rate tends to be reduced. Therefore, the nitrogen concentration is preferably within the above composition range.

As mentioned earlier, gas holder (e.g., typical gas holder used in steelworks) General composition of metallurgical furnace generation exhaust gas to be stored in the, CO: 50~70vol%, CO 2 : 10 ˜20 vol%, N ₂ : 10 to ₂₀ vol%, H ₂ : 0 to 5 vol% (including saturated steam in addition), and this composition is high in the composition of the above general metallurgical furnace generated exhaust gas. It corresponds to the CO concentration composition. Since the gas stored in the gas holder is used as fuel gas at each factory in the steelworks, it is necessary to prevent a decrease in combustion efficiency at the use destination. Therefore, setting the lower limit value of the CO concentration in the gas as a storage condition in the gas holder is the reason why the composition has a high CO concentration.
In the method of the present invention, even with an exhaust gas having a relatively high CO concentration such as stored in a general gas holder used in a steelworks, the composition of the exhaust gas generated in the above-mentioned general metallurgical furnace is used. even, it can be utilized as an exhaust gas (g _0).

By the way, in the case of a metallurgical furnace-generated exhaust gas containing a relatively high concentration of CO and having a low N ₂ concentration, such as an exhaust gas generated in a converter, a shift reaction is performed by adding excess steam to the exhaust gas. However, some of the exhaust gases generated from metallurgical furnaces contain carbon monoxide but have a relatively high nitrogen concentration (for example, those with a relatively low carbon monoxide concentration and a high nitrogen concentration such as blast furnace gas). For such exhaust gas generated in a metallurgical furnace, at least a part of the nitrogen contained is separated (removed) to increase the carbon monoxide concentration, and then an excess water vapor is added to cause a shift reaction. You may do it. If the nitrogen concentration in the metallurgical furnace generated exhaust gas exceeds 30 vol%, it is advantageous to provide a nitrogen separation step to separate (remove) at least a part of nitrogen from the metallurgical furnace generated exhaust gas because the shift reaction becomes faster.

As typical exhaust gas that is preferably subjected to nitrogen separation, blast furnace gas can be mentioned, but in addition to this, exhaust gas generated from an electric furnace or a shaft furnace operating under a condition where the nitrogen concentration becomes high can be mentioned. it can. It is also possible to perform a shift reaction after further separating the nitrogen from the metallurgical furnace generated exhaust gas containing a relatively high concentration of carbon monoxide, such as converter gas, and further increasing the carbon monoxide concentration. .
There is no special restriction on the method for separating nitrogen from the exhaust gas generated in the metallurgical furnace, and any method such as adsorption separation method or distillation separation method can be applied, but because the difference in boiling point between nitrogen and carbon monoxide is small, adsorption A separation method is particularly preferred. For example, since activated carbon supporting Cu ⁺ , which is known as a CO adsorbent, also adsorbs CO ₂ , blast furnace gas (general composition: N ₂ : 50 vol%, CO ₂ ) is obtained by PSA method using Cu ⁺ supported activated carbon as an adsorbent. : _25vol%, CO 2: approximate composition as desorbed gas from 25 vol%) is _{N 2: 15vol%, CO:} 45vol%, CO 2: it is possible to obtain a 40 vol% of the gas, which separates the nitrogen in the blast furnace gas Thus, the carbon monoxide is concentrated.

The shift reaction in the method of the present invention may be carried out by a known method and is not particularly limited. Generally, water vapor is added to the metallurgical furnace-generated exhaust gas (g ₀ ) in advance, and this is introduced into a fixed bed reactor filled with a catalyst to perform a shift reaction. Alternatively, the water vapor to be added in advance may be partially used, the catalyst may be packed in multiple stages in the reactor, and the remaining water vapor may be added between the catalyst layer and the catalyst layer. There is no restriction | limiting also about a shift reaction catalyst, Well-known catalysts, such as an iron type and copper type, can be used.
If water vapor, hydrogen, and carbon dioxide are added to the metallurgical furnace-generated exhaust gas (g ₀ ) without performing the shift reaction as in the present invention method, the organic material reforming obtained by the shift reaction in the present invention method can be performed. However, in such a method, expensive hydrogen gas and carbon dioxide gas must be added in addition to water vapor, resulting in high cost.

  In the method of the present invention, the mixed gas (g) for reforming the organic substance obtained by the shift reaction contains water vapor, hydrogen and carbon dioxide gas, and there is no particular limitation on the concentration thereof, but the following For the reason, the water vapor concentration is preferably 5 vol% or more. That is, when the water vapor concentration is low, the decomposition rate of organic substances such as plastics is low, but by setting the water vapor concentration to 5 vol% or more, a certain level of organic material decomposition rate can be secured, and the rate of gas product production ( Gasification rate) ・ Liquid product production rate (liquefaction rate) can be maintained at a constant level, and the amount of heavy components produced can be reduced. That is, this water vapor concentration is a preferred water vapor concentration for the organic molecule lowering reaction.

On the other hand, when the water vapor concentration is high, CO ₂ tends to remain in the reforming reaction product gas of the organic substance (gas generated by low molecular weight reforming of the organic substance; the same applies hereinafter), and also a gas product / liquid production However, if the water vapor concentration is 70 vol% or less, the residual CO _{2 in} the reforming reaction product gas can be suppressed, and the LHV of the gas product / liquid product can be reduced. The decrease can also be suppressed. For this reason, the water vapor concentration is preferably 70 vol% or less.
Further, from the viewpoint of ensuring the decomposition rate of the organic substance, both the hydrogen concentration and the carbon dioxide concentration of the mixed gas (g) are preferably 5 vol% or more.

Further, for the following reasons, the more preferable composition of the mixed gas (g) for organic substance reforming is: water vapor concentration: 20 vol% or more (preferably 70 vol% or less), hydrogen concentration: 10-40 vol%, carbon dioxide gas Concentration: 10 to 40 vol%. In addition, it does not prevent that other gas components (for example, nitrogen etc.) are contained in this mixed gas (g). By setting the water vapor concentration to 20 vol% or more, the decomposition rate of the organic substance can be sufficiently increased, and the LHV of the gas product can be increased. By setting the hydrogen concentration to 10 vol% or more (more preferably 12 vol% or more), it is possible to suppress CO ₂ from remaining in the gas product even when a reforming reaction of an organic substance is performed at a relatively low temperature. be able to. By setting the carbon dioxide gas concentration to 10 vol% or more (more preferably 13 vol% or more), the amount of hydrocarbons and CO produced in the gas product increases. Moreover, the decomposition rate of organic substances, such as a plastic, can be made into a preferable level by making hydrogen concentration and carbon dioxide gas concentration into 40 vol% or less. Moreover, from the above viewpoints, a more preferable gas composition of the mixed gas (g) is: water vapor concentration: 25 vol% or more (preferably 65 vol% or less), hydrogen concentration: 15-35 vol%, carbon dioxide concentration: 15-35 vol. %. In addition, it does not prevent that other gas components (for example, nitrogen etc.) are contained in this mixed gas (g).

  In addition, as one of the characteristics of the method of the present invention, the ratio of the amount of gas product produced and the amount of liquid product produced in the reforming of the organic substance is determined depending on the water vapor concentration of the mixed gas (g) for reforming the organic substance. Can be controlled. That is, when the water vapor concentration of the mixed gas (g) is 50 vol% or more, a gas product is mainly generated (that is, the amount of gas product produced> the amount of liquid product produced), and the water vapor concentration is 40 vol% or less. The liquid product is mainly produced (ie, the amount of gas product produced <the amount of liquid product produced). In addition, since the influence of hydrogen concentration and carbon dioxide gas concentration is not as remarkable as the influence of water vapor concentration, it may be within the above-described preferred range.

  Next, in the present invention, the reforming reaction of the organic substance is performed by bringing the mixed gas (g) (shift reaction product gas containing hydrogen, carbon dioxide gas, and water vapor) obtained by the shift reaction as described above into contact with the organic substance. (Low molecular weight reaction) is generated, and hydrogen is generated by steam reforming the hydrocarbon generated by the reforming reaction. The production of hydrogen by this series of reforming reactions may be performed in one reactor, or the production of hydrocarbons (gas products and liquid products) by reforming reactions of organic substances (reduction of molecular weight). In addition, the production of hydrogen by steam reforming of hydrocarbons may be performed in a separate reactor.

In the former case, using a mixed gas (g) containing or added with steam necessary for steam reforming, reforming reaction of the organic substance and steam of the product generated by this reforming reaction The reforming is carried out simultaneously in one reactor.
In the latter case, a reforming reaction of an organic substance is performed in a reforming reactor, and a product (mainly a hydrocarbon, which may contain an unreacted organic substance) generated by the reforming reaction. The same applies hereinafter) to the steam reformer to perform steam reforming. In this case, for example, among hydrocarbons (low molecular weight reaction products), the gas product may be used as fuel, and only the liquid product may be steam reformed. Alternatively, the liquid product may be utilized for other applications, and only the gaseous product may be steam reformed. As a method for separating a low molecular weight substance into a gas product and a liquid product, the distillation method is the simplest, but other methods may be used and there are no particular restrictions.
By separating the gas product from the low molecular weight material and using only this gas product as the raw material gas for hydrogen production, it is possible to remove plastic-derived residues and chlorine, and relatively high molecular weight such as light oil. There is also an advantage that problems such as soot formation in steam reforming of hydrocarbons, problems such as damage and thinning of the compressor and piping, and blockage can be avoided.

In the method of the present invention, steam is required for steam reforming in order to produce hydrogen by steam reforming a hydrocarbon produced by a reforming reaction (lower molecular weight reaction) of an organic substance. Here, the amount of water vapor necessary for the steam reforming reaction of the hydrocarbon (reduced molecular weight product) generated by the reforming reaction of the organic substance is expressed by the following equation (2), where (CH ₂ ) n is the hydrocarbon. Can be sought.
Steam required for steam reforming: (CH ₂ ) n + nH ₂ O → nCO + 2nH ₂ (2)
Therefore, it is necessary to add steam necessary for such steam reforming at an appropriate stage.

Steam required for steam reforming can be added, for example, in any one of the following stages (i) to (iii) (form).
(I) An excess steam is added to the exhaust gas (g ₀ ) to cause a shift reaction, and when obtaining a mixed gas (g), steam necessary for steam reforming is added. That is, steam is added to the exhaust gas (g ₀ ) so that the amount of steam calculated by the above equation (2) remains until steam reforming (start).
(Ii) Steam necessary for steam reforming is added to the mixed gas (g) produced by the shift reaction.
(Iii) Steam necessary for steam reforming is added to the product generated by the reforming reaction of the organic substance.
However, it is particularly preferable to add steam in the step (iii) in that the shift reaction of the exhaust gas (g ₀ ), the reforming reaction of the organic substance, and the steam reforming reaction can be individually controlled.

Hereinafter, the modification (reduction in molecular weight) of the organic substance by the mixed gas (g) will be described.
In the method of the present invention, there is no particular limitation on the organic material to be reduced in molecular weight by modification, but high molecular weight organic materials are suitable, for example, plastic, oil-containing sludge, waste oil, biomass, etc. One or more of these can be targeted.
Although there is no special restriction | limiting in the kind of target plastic, For example, an industrial waste type | system | group, a target plastic of the container packaging recycling law etc. can be mentioned. More specifically, polyolefins such as PE and PP, thermoplastic polyesters such as PA and PET, elastomers such as PS, thermosetting resins, synthetic rubbers, foamed polystyrene and the like can be mentioned. In addition, inorganic substances such as fillers are added to many plastics. However, in the present invention, such inorganic substances are not involved in the reaction, so that they are reformed (low molecular weight) reactors (organic substances) as solid residues. Is discharged from a reactor for reducing the molecular weight by modifying the same. In addition, the plastic is pre-cut into an appropriate size as required, and then charged into the reforming reactor.

In addition, when the plastic contains a chlorine-containing resin such as polyvinyl chloride, chlorine is generated in the reforming reactor, and this chlorine may be contained in a gas product or a liquid product. Therefore, when there is a possibility that the plastic contains a chlorine-containing resin, a chlorine absorbent such as CaO is introduced into the reforming reactor and is not contained in a gas product or a liquid product in which chlorine is generated. It is preferable to do so.
Oil-containing sludge is a sludge-like mixture generated in an oil-containing waste liquid treatment step, and generally contains about 30 to 70% by mass of water. Examples of the oil in the sludge include, but are not limited to, various mineral oils, natural and / or synthetic oils and fats, and various fatty acid esters. In addition, in order to improve handling property, such as when supplying oil-impregnated sludge to the reforming reactor, moisture in the sludge may be reduced to about 30 to 50% by mass by a method such as centrifugation.

  Examples of the waste oil include, but are not limited to, various used mineral oils, natural and / or synthetic fats and oils, and various fatty acid esters. Moreover, the mixture of these 2 or more types of waste oil may be sufficient. In addition, in the case of waste oil generated in the steel mill rolling process, it generally contains a large amount of water (usually more than about 80% by mass), but this water is also reduced in advance by a method such as specific gravity separation. It is advantageous in terms of handleability.

Examples of biomass include, but are not limited to, sewage sludge, paper, construction waste, thinned wood, and other processed biomass such as waste solid fuel (RDF). Since biomass usually contains a large amount of water, it is preferable to dry it beforehand in view of energy efficiency. In addition, in the case of biomass containing relatively high concentrations of alkali metals such as sodium and potassium, alkali metals may be deposited in the reforming reactor. It is preferable to keep it. In addition, large biomass such as construction waste is cut in advance and charged into the reforming reactor.
When the organic substance contains water, water vapor is generated in the reforming reactor. Therefore, an excess ratio of water vapor to be added in the shift reaction in consideration of the amount, and further to the mixed gas (g) Determine the amount of water vapor to be added.

Reaction temperature at the time of reforming the organic material (the reaction temperature in the case where the lowering of the molecular weight by reforming the organic material and the steam reforming of the product generated by this reforming are simultaneously performed in one reactor) The same applies to the following depending on the type of organic substance.
In the case of plastic or biomass, the reaction temperature is suitably about 400 to 1000 ° C. (preferably 600 to 900 ° C.). When the reaction temperature is less than 400 ° C., the decomposition rate of plastic and biomass is low, while when it exceeds 1000 ° C., carbonaceous production increases. When the reaction temperature is less than 600 ° C., the hydrogen yield tends to be low although the decomposition rate of plastic and biomass is high.

In the case of oil-containing sludge or waste oil, the reaction temperature is suitably about 300 to 900 ° C (preferably 600 to 800 ° C). If the reaction temperature is less than 300 ° C, the decomposition rate of the oil-containing sludge and waste oil is low. On the other hand, if the reaction temperature exceeds 900 ° C, there is no effect on the reforming (lower molecular weight) characteristics of the oil-containing sludge and waste oil. It is not economical because of the high temperature. When the reaction temperature is less than 600 ° C., the hydrogen yield tends to be low although the decomposition rate of oil-containing sludge and waste oil is high.
In addition, when a mixture of plastic and / or biomass and oil-containing sludge and / or waste oil is targeted, the reaction temperature is suitably about 400 to 1000 ° C. (preferably 600 to 900 ° C.) in view of the above. In addition, the influence of reaction temperature with respect to the ratio of the production amount of a gaseous product and the production amount of a liquid product is hardly seen. In addition, since almost no influence of pressure is observed, it is economical to operate the reforming reactor at a slight pressure of about normal pressure to about 3 kg / cm ² G.

In the reforming of organic substances (the same applies to the case of reducing the molecular weight by reforming organic substances and steam reforming of the products generated by this reforming simultaneously in one reactor) The type of the vessel is not particularly limited, but organic substances such as plastics can move smoothly in the reactor and can be efficiently contacted with the mixed gas (g) for organic substance modification. A horizontal moving bed reactor is preferred.
In the present invention, a catalyst is not particularly required for reforming the organic substance, but the reaction may be carried out by filling the catalyst. As the catalyst, one or more catalysts each having steam reforming activity, carbon dioxide reforming activity, hydrogenation activity, and hydrocracking activity can be used. Specific examples include Ni-based reforming catalysts, Ni-based hydrogenation catalysts, Pt / zeolite-based petroleum refining catalysts, and the like. Also, converter-generated dust, which is known to be composed of fine Fe particles, can be used as a reforming catalyst or a hydrocracking catalyst.

When packing the catalyst, the contact between the organic substance such as plastic and the catalyst is good, so a vertical reforming reactor is used instead of a horizontal moving bed reforming reactor such as a rotary kiln. It may be adopted. In this case, it is preferable that the mixed gas (g) is supplied from the lower part and / or the side part from the upper part of the reforming reactor because the contact between the mixed gas (g) and the organic substance or the catalyst is good.
As a vertical reforming reactor, a general fixed bed reactor used in the chemical industry can be used, but in particular, when a method of supplying a mixed gas (g) from the lower part of the reforming reactor is employed. For the reforming reactor, a vertical moving bed reactor typified by a blast furnace or a shaft furnace, which is an iron manufacturing facility, or a batch reactor typified by a converter can also be used. When a vertical moving bed reactor is used as a reforming reactor, an organic substance and a catalyst are continuously supplied from the upper part of the furnace, and a mixed gas (g) is continuously supplied from the lower part of the furnace to make countercurrent contact. It is preferable to continuously extract the gaseous product from the furnace and the liquid product and the catalyst from the lower part of the furnace because the reaction efficiency is increased. When a batch reactor is used as a reforming reactor, an organic substance and a catalyst are introduced into the furnace, and then a mixed gas (g) is continuously supplied from the lower part of the furnace. It is possible to adopt a system similar to converter blowing, in which the liquid product and the catalyst are continuously extracted and the furnace is extracted after the reaction for a certain time.
A fluidized bed reactor may be used as the organic material reforming reactor. The case of using this fluidized bed reactor will be described in detail later.

Hereinafter, steam reforming of a product generated by organic substance reforming (lower molecular weight) will be described.
The product to be steam reformed contains the steam added in any one of the steps (i) to (iii) mentioned above, and reacts with this at a predetermined temperature in the reactor. Modification is made. By this steam reforming, the hydrocarbon and steam react to produce hydrogen and carbon monoxide.
The steam reforming of the hydrocarbon can be performed by a known method, and the condition may be a general condition as follows.

  When the reforming of the organic substance and the steam reforming of the product generated by this reforming are performed in separate reactors, the reaction temperature is suitably about 500 to 1000 ° C, particularly preferably about 600 to 800 ° C. . If the reaction temperature is too low, it is disadvantageous in terms of chemical equilibrium, the steam reforming reaction rate is slow, and the hydrogen yield is low. In addition, problems such as soot generation occur. On the other hand, when the reaction temperature is too high, the steam reforming characteristics are not affected, but the heat efficiency is deteriorated and the heat resistance of the reactor material is problematic. The reaction temperature in the case where the reforming of the organic substance and the steam reforming of the product generated by the reforming are simultaneously performed in one reactor is as described above.

The amount of water vapor added is suitably at least twice the stoichiometric amount of water. If the added amount is too small, problems such as a decrease in reaction efficiency and a temperature increase in the subsequent shift reaction occur, and if the added amount is too large, problems such as a decrease in thermal efficiency occur.
The pressure for the reaction is preferably a low pressure in terms of the reaction, but in order to prevent accidents due to air leakage, for example, a pressure of about normal pressure to about 3 kg / cm ² G is appropriate.
As the catalyst, a general nickel-based reforming catalyst is appropriate and can be procured at a low cost.
The type of the reactor used in the steam reforming is not particularly limited, but a vertical type reforming furnace generally used for steam reforming of natural gas has a proven track record and is particularly preferable. As the type of the reactor, an external heat type or internal heat type reforming furnace, an autothermal type reforming furnace, or the like can be used.

In addition, since carbon monoxide is generated by steam reforming, the above-described steam reforming of the organic substance (however, the reforming reaction of the organic substance and the steam reforming of the product generated by this reforming reaction are performed in one reaction). In addition, steam or / and water is further added to the gas produced in step 2), and carbon monoxide is converted to hydrogen by a shift reaction. The amount of production (production) can be increased. Hereinafter, this shift reaction will be described.
This shift reaction is performed by adding steam or / and water to the gas generated by steam reforming and reacting at a predetermined temperature in the shift reactor. By the shift reaction, carbon monoxide in the gas reacts with water vapor to produce hydrogen and carbon dioxide. Therefore, the gas (reaction product) after the shift reaction is a hydrogen-rich mixed gas (the balance is carbon dioxide, nitrogen, water vapor, etc.) or a mixed gas substantially composed of hydrogen and carbon dioxide. This shift reaction of the reaction product gas of the steam reforming can be performed by a known method, and no special conditions are required. However, in order to increase the hydrogen yield, it is preferable to employ the low temperature shift method as described below.

The reaction temperature is suitably about 200 to 300 ° C. Therefore, the shift reaction is carried out after cooling the steam reforming reaction product gas to about 200 to 300 ° C., and then water or / and low pressure (for example, 180 ° C. or less). It is preferable to carry out by adding water vapor. This is because the hydrogen yield is higher when the shift reaction is performed at about 200 to 300 ° C. due to the equilibrium.
Here, the amount of water and / or steam required for the shift reaction of the reaction gas produced by steam reforming can be obtained by the following equation (3).
Water or / and water vapor required for the shift reaction: nCO + nH ₂ O → nCO ₂ + nH ₂ (3)
Therefore, water or / and steam necessary for such a shift reaction are added to the reaction product gas of the steam reforming, and the shift reaction is performed in the shift reactor.

However, the addition amount of water or / and water vapor is suitably 1.5 times or more and 5 times or less of the stoichiometric water amount. If the added amount is too small, a problem of chemical equilibrium occurs, and if the added amount is too large, a problem of thermal efficiency occurs. Water or / and steam may be introduced into the shift reactor after adding the entire required amount to the reaction product after steam reforming, or a part of water or / and steam may be introduced into the shift reactor. You may make it add. The method of adding water or / and water vapor into the shift reactor is particularly preferable because it also controls the reaction temperature of the shift reaction, which is an exothermic reaction.
The pressure for the reaction is not particularly dependent on the pressure in the reaction, but in order to prevent accidents due to air leakage, for example, a pressure of about normal pressure to about 1 kg / cm ² G is appropriate.
As the catalyst, a general copper-based low temperature shift catalyst is suitable and can be procured at a low cost.

There are no particular restrictions on the type of shift reactor, but a fixed bed reactor is usually used. Since the shift reaction is an exothermic reaction, it is preferable to recover heat with a heat exchanger installed on the downstream side of the shift reactor.
The hydrogen-rich mixed gas obtained by the shift reaction can also be used as a high-concentration hydrogen-containing gas as fuel, but normally, hydrogen is separated from the mixed gas to produce high-purity hydrogen gas (product gas). To do. There are various methods for separating hydrogen from the mixed gas, and any of them may be applied. For example, a distillation separation method, a PSA method, a cryogenic separation method and the like can be mentioned, but other methods may be used.

FIG. 2 schematically shows an embodiment of a production facility for producing hydrogen by the method of the present invention. 1 is a shift reactor for obtaining a mixed gas (g), and 2 is an organic substance modification. A quality reforming reactor 3 is a steam reforming reactor.
First, in the shift reactor 1, hydrogen gas and carbon dioxide generated by the shift reaction and the shift reaction were not consumed by adding excess water vapor to the metallurgical furnace-generated exhaust gas (g ₀ ) to cause the shift reaction. A mixed gas (g) containing water vapor is generated. This shift reaction product gas (g) is introduced into the reforming reactor 2, where it comes into contact with an organic substance such as plastic, thereby causing a reaction that modifies the organic substance to lower its molecular weight. The product (hydrocarbon) generated by this reforming reaction (reduction of molecular weight of organic substance) is introduced into the steam reforming reactor 3, and any one of steps (i) to (iii) mentioned above Particularly preferably, it reacts with the steam added in the step (iii) and undergoes steam reforming to produce hydrogen. That is, hydrocarbon and water vapor react to generate hydrogen and carbon monoxide, and a hydrogen-rich mixed gas (high concentration hydrogen-containing gas) is obtained.

In addition, the production facility can be provided with a shift reactor 5 shown in phantom lines in FIG. 2. The gas generated in the steam reforming reactor 3 is introduced into the shift reactor 5 and water or / and steam is added. This causes a shift reaction. By this shift reaction, carbon monoxide and water vapor in the gas react to produce hydrogen and carbon dioxide, and a more hydrogen-rich mixed gas (high concentration hydrogen-containing gas) is obtained.
The obtained hydrogen-rich mixed gas (high-concentration hydrogen-containing gas) is passed through a gas separation device (not shown) such as PSA as necessary to separate hydrogen to obtain high-purity hydrogen gas. Also good.

FIG. 3 schematically shows another embodiment of a production facility for producing hydrogen by the method of the present invention. In this production facility, reforming of an organic substance and production generated by this reforming are shown. The steam reforming of the product is performed simultaneously in one reforming reactor 4. That is, the shift reaction product gas (g) generated in the shift reactor 1 is introduced into the reforming reactor 4 where the organic material such as plastic is reformed to reduce the molecular weight, and this reforming reaction ( The product (hydrocarbon) produced by the reduction of the molecular weight of the organic substance is steam-reformed, and a hydrogen-rich mixed gas (high concentration hydrogen-containing gas) is obtained.
Similarly to the production facility of FIG. 2, a shift reactor 5 indicated by a virtual line in FIG. 3 can be provided, and the gas generated in the reforming reactor 4 is introduced into the shift reactor 5, and water or Water vapor is added to cause a shift reaction, and a more hydrogen-rich mixed gas (high concentration hydrogen-containing gas) is obtained.
The obtained hydrogen-rich mixed gas (high-concentration hydrogen-containing gas) is passed through a gas separation device (not shown) such as PSA as necessary to separate hydrogen to obtain high-purity hydrogen gas. Also good.

As shown in an embodiment of FIG. 5 to be described later, it is preferable to make effective use of energy in the manufacturing facility as follows.
(A) Heat recovery is performed from the gas generated by steam reforming and / or the gas generated by the shift reaction after steam reforming, and the recovered heat is converted into steam for steam reforming and / or steam for shift reaction. Used as a heat source for generating
(A) A part of the gas product produced by the reforming of the off-gas and / or organic substance after separating hydrogen from the gas obtained by steam reforming or the subsequent shift reaction is treated with a steam reforming reactor. Used as a heat source fuel.
In the method (a), heat recovery may be performed with a general exhaust heat boiler to generate water vapor. The off gas in the method (a) is a residual gas obtained by separating high-purity hydrogen as a product from a hydrogen rich gas supplied to a gas separation device (hydrogen purification device). Since the off-gas is separated from hydrogen, which is a combustible component, the combustion heat is usually lower than that of the hydrogen-rich gas supplied to the gas separation device (hydrogen purification device). Thus, off gas is a gas with low combustion heat and reduced utility value as a heat source, so it is preferable to use it near the off gas generation source from the viewpoint of energy efficiency, and as a heat source for the steam reforming reactor. The use of is common.

In the method of the present invention, an organic substance is reformed (lower molecular weight) with a mixed gas (g), the product generated by this reforming reaction is steam reformed, and further, a shift reaction is performed in a series of steps. It is possible to separate a gas product from a product generated by a material reforming reaction, steam reform the gas product, and further perform a shift reaction.
As a method for separating a gaseous product from a low molecular weight substance, the distillation method is the simplest, but other methods may be used without any particular restriction.
The separated gas product is a mixed gas mainly composed of carbon monoxide and light hydrocarbons (the balance is nitrogen or the like) or a mixed gas substantially consisting of carbon monoxide and light hydrocarbons.
As mentioned earlier, by separating the gas product from the low molecular weight material and using only this gas product as the raw material gas for hydrogen production, it is possible to remove plastic-derived residues and chlorine, There is also an advantage that problems such as soot formation in steam reforming of relatively high molecular weight hydrocarbons such as light oil, and problems such as damage and thinning of the compressor and piping, blockage, etc. can be avoided.

  Steam reforming of a gas product is performed by adding steam to the gas product and reacting at a predetermined temperature in a steam reforming reactor. By this steam reforming, light hydrocarbons in the gas product and steam react to generate hydrogen and carbon monoxide. Therefore, the gas (reaction product) after this steam reforming is usually a mixed gas mainly composed of hydrogen and carbon monoxide (the balance is nitrogen, steam, etc.) or a mixture consisting essentially of hydrogen and carbon monoxide. Gas. The conditions for steam reforming may be the general conditions as described above. The conditions for the shift reaction performed after the steam reforming may be the general conditions described above.

FIG. 4 schematically shows an embodiment of equipment for performing a shift reaction of metallurgical furnace-generated exhaust gas and reforming to reduce the molecular weight of an organic substance in this method. In FIG. 4, 2 is a vertical reforming reactor having a gas dispersion plate 200 at the bottom, and 6 is a liquid product for separating the product produced in the reforming reactor 2 into a gas product and a liquid product. A collector 7 is a gas cooler for cooling the separated gas product.
In this equipment, the lowermost layer in the reforming reactor 2 is filled with a plastic a that has been crushed in a granular form, a metal net b is placed on the upper part, and a catalyst c (for example, Ni catalyst) is further placed on the upper part. Filled. The shift reaction product gas (g) generated in the shift reactor 1 is introduced into the bottom of the reforming reactor 2, and is supplied into the reactor through the gas dispersion plate 200, and rises in the reactor. The reformed product produced by the reaction between the plastic a and the shift reaction product gas (g) is discharged from the upper part of the reforming reactor 2 and separated into a gas product and a liquid product by the liquid product collector 6. Is done. The separated gas product is cooled by the gas cooler 7 and then sent to the next step.

FIG. 5 schematically shows an embodiment of equipment for performing steam reforming and shift reaction of a gas product obtained by reforming an organic substance in this method. In FIG. 5, 8 and 12 are compressors, 9 and 10 are heat exchangers, 13 is a cooler, 14 is a gas separation device, 15 and 16 are gas lines, and 17 is a steam supply line.
For example, in a facility as shown in FIG. 4, the gas product produced by reforming (lowering the molecular weight) of the organic substance and then separated from the liquid product is pressurized by the compressor 8 and then subjected to a steam reforming reaction. Introduced into the vessel 3. Steam is introduced into the steam reforming reactor 3 through the steam supply line 17 and the gas product is steam reformed. The gas obtained by this steam reforming is cooled by heat exchange with water or steam flowing through the steam supply line 17 in the heat exchanger 9 and then introduced into the shift reactor 5. Steam (or water) is introduced into the shift reactor 5 from the steam supply line 17 to perform a shift reaction. The hydrogen rich gas obtained by this shift reaction is cooled by exchanging heat with water flowing through the steam supply line 17 in the heat exchanger 10, and then water is separated in the separator 11. Further, after being pressurized by the compressor 12 and cooled by the cooler 13, high purity hydrogen is obtained by separating hydrogen by a gas separation device 14 (for example, a PSA gas separation device). In this embodiment, in the heat exchangers 9 and 10, heat recovery of the gas generated by steam reforming and the gas generated by the shift reaction after steam reforming is performed, and steam for steam reforming and steam for shift reaction are performed. It is used as a heat source for generating Further, through the gas lines 15 and 16, a part of the gas product as a raw material and the off-gas of the gas separation device 14 (residual gas obtained by separating high-purity hydrogen as a product in the gas separation device 14) are converted into a steam reforming reactor. 3 is used as a heat source fuel.

Hereinafter, when a fluidized bed reactor is used as a reforming reactor for modifying an organic substance to lower the molecular weight, that is, the mixed gas (g) is brought into contact with the organic substance in the fluidized bed to reform the organic substance. The case of lowering the molecular weight will be described.
When plastics are used to reduce the molecular weight batch-wise, this is not a major problem, but when the reaction is carried out in a flow-type fixed bed reactor, the supply of reaction heat becomes the rate-determining factor and the plastics are fused in the reactor. In addition, there are cases in which the heat efficiency is deteriorated by supplying heat higher than necessary to prevent fusion, and the plastic is carbonized by the high-temperature supply heat. On the other hand, the fluidized bed reactor is characterized by the fact that the temperature in the fluidized bed is almost uniform and the heat exchange is very fast, so that the problems that may occur in the fixed bed reactor described above are avoided. Can do. In other words, by reducing the molecular weight of organic substances using a fluidized bed with a high heat transfer rate, it is possible to prevent the rate of supply of reaction heat necessary for the reduction of molecular weight from being controlled, and high molecular weight organic materials such as plastics in the reactor. It is possible to prevent troubles such as a substance being fused and clogged.

Further, when reforming an organic substance (lowering the molecular weight) in a fluidized bed reactor, the true density is 4 to 8 g / cm ³ as at least a part of the fluidized medium in the fluidized bed (preferably the main body of the fluidized medium). Therefore, it is preferable to use a powder (f) containing at least one selected from Fe, Ni, and Cr. Fe, Ni, and Cr are all active in this reaction, and the low molecular weight reaction proceeds with high efficiency by the powder (f) functioning also as a catalyst. On the other hand, in the conventional plastic gasification technology using a fluidized bed, sand is often used as a fluidized medium. However, sand not only has no catalytic activity, but also has a slightly larger particle size as a fluid medium, and the conditions under which a stable fluidized bed can be formed are limited, making it difficult to deal with various raw materials. In addition, the presence form of Fe, Ni, Cr contained in a granular material (f) does not ask | require a distinction, such as a metal and an oxide. The reason why the true density of the powder (f) is 4 to 8 g / cm ³ will be described later.

  The total content of Fe, Ni and Cr in the powder (f) is preferably about 20 to 90% by mass, and more preferably about 30 to 80% by mass. When the content is less than 20% by weight, the true density of the granular material (f) becomes small, so that the granular material (f) scattered in the gas discharged from the fluidized bed reactor is separated from the ash content of the organic substance. The collection (collection in a state where both are separated) tends to be insufficient. On the other hand, if the content exceeds 90% by mass, the true density becomes excessive and the fluidity is lowered.

FIG. 6 shows an embodiment of equipment for reforming to reduce the molecular weight of an organic substance using a fluidized bed reactor, wherein 20 is a fluidized bed reactor that is a reforming reactor, and 21 is a fluidized bed reactor. A discharge pipe for discharging gas from the bed reactor 20, 22a is a primary dust collector (upstream first stage dust collector) provided in the discharge pipe 21, and 22b is a secondary dust collector (downstream second stage dust collector). Generally, the primary dust collector 22a is a cyclone, but the type of the secondary dust collector 22b is arbitrary, and may be a dry dust collector or a wet dust collector. When the secondary dust collector 22b is a dry dust collector, the exhaust gas is not cooled to the condensation temperature of the liquid product, so that the product passing through the secondary dust collector 22b remains in a gaseous state. A cooler, an oil / water separator, etc. are installed on the downstream side, and separated into gas products, liquid products, and waste water. On the other hand, when the secondary dust collector 22b is a wet dust collector, the exhaust gas is cooled and the liquid product is condensed. Therefore, the product passing through the secondary dust collector 22b is a gas product and is captured by the secondary dust collector 22b. The collected material will be a mixture of ash, wastewater, and liquid product. Therefore, an oil / water separator is installed in the mixture discharge system to separate the liquid product.
In FIG. 6, the primary dust collector 22 a is installed outside the fluidized bed reactor 20, but may be installed inside the fluidized bed reactor 20.

In the fluidized bed reactor 20, the mixed gas (g) is introduced into the lower air box portion 202 of the gas dispersion plate 201, and the mixed gas (g) is blown out of the gas dispersion plate 201, whereby the gas dispersion plate 201. A fluidized bed 23 made of a fluidized medium is formed above. An organic substance such as plastic is supplied to the fluidized bed 23 from the upper part of the fluidized bed reactor 20 and is reduced in molecular weight by reacting with the mixed gas (g) in the fluidized bed 23 to become a gas product. The gas (g _p ) containing the gaseous product is discharged through the discharge pipe 21, and then the ash content of the fluid medium and organic substances scattered in the gas (g _p ) is captured by the primary dust collector 22a and the secondary dust collector 22b. However, the fluid medium and the organic ash are collected as separated as possible. In other words, the primary dust collector 22a mainly collects the fluid medium and prevents ash from being collected as much as possible, and the secondary dust collector 22b mainly collects the ash of organic substances. For this purpose, as will be described later, it is important to optimize the true density of the granular material (f) that is a fluid medium. The collected matter mainly composed of the fluidized medium collected by the primary dust collector 22 a is circulated to the fluidized bed reactor 20 through the return pipe 24. Note that the primary dust collector 22a and the return pipe 24 may be disposed on the free board portion in the upper part of the fluidized bed reactor 20. The gas (g _p ) that has passed through the secondary dust collector 22b is recovered, but the gas product contained in the gas (g _p ) may be partially condensed to form a liquid product.
As described above, the gas (g _p ) discharged from the fluidized bed is passed through the dust collector, the fluid medium contained in the gas (g _p ) is collected, and the collected fluid medium is circulated to the fluidized bed. It is preferable.

The powder particles (f) constituting the fluid medium have a true density of 4 to 8 g / cm ³ , more preferably 4 to 7.5 g / cm ³ . Since ash content of the fluidized medium granular material (f) and organic substances in the gas discharged from the fluidized bed reactor 20 (g _p) as described above is scattered, they are gas dust collector (g _p) Of these, the granular material (f) is circulated in the fluidized bed reactor 20. When the true density of the granular material (f) is less than 4 g / cm ³ , since the density difference from the ash content of the organic substance is small, it becomes difficult to separate and collect from the organic ash content. Separation of ash tends to be insufficient. Specifically, in FIG. 6, it becomes difficult to mainly collect only the granular material (f) in the primary dust collector 22a, and a considerable amount of organic ash is also collected. As a result, the granular material (f) separated from the gas (g _p ) and circulated to the fluidized bed reactor 20 is diluted with ash that is inert to the low molecular weight reaction, and the catalyst of the fluidized bed 23 The activity will decrease continuously. On the other hand, when the true density of the granular material (f) exceeds 8 g / cm ³ , the fluidity as a fluid medium decreases. Here, a true density means the density measured using a pycnometer based on JIS-K-0061.

Even when the fluid medium collected and separated by the primary dust collector 22a is not circulated through the fluidized bed reactor 20, if the true density of the powder (f) is less than 4 g / cm ³ , the powder (f) It is difficult to collect the ash separately, and the powder (f) is still diluted by the ash. When steelmaking dust as described later is used as the granular material (f), this steelmaking dust is very inexpensive, so it is not necessary to circulate the steelmaking dust collected by the dust collector to the fluidized bed reactor for reuse. However, since the steelmaking dust is usually returned to the ironmaking process to recover the iron content, if a considerable amount of ash is contained therein, the amount of slag generated in the ironmaking process is increased by this ash. Therefore, in any case, in order to prevent the granular material (f) collected from the gas (g _p ) from being diluted with ash, the true density of the granular material (f) is 4 g / cm ³ or more. It is preferable.

As the granular material (f) that is a fluid medium and functions as a catalyst, a known Ni-based reforming catalyst or Ni-based hydrogenation catalyst can be used, but (a) the catalyst activity is high because it contains a large amount of iron. Steelmaking for reasons such as being high, (a) having a true density in the range of ⁴ to 8 g / cm ³ and being fine particles and therefore suitable as a fluid medium, (c) being available in large quantities and being inexpensive. It is particularly preferable to use iron-containing dust generated in the process (hereinafter referred to as “steel-making dust” for convenience of explanation). Steelmaking dust generally contains 30% by mass or more of iron. Since this steelmaking dust is generally collected by a wet process, a drying process is necessary, but a classification process or the like is not necessary.

Steelmaking dust is iron-containing dust generated mainly in a steelmaking process performed using a converter, and examples of the steelmaking process include a dephosphorization process, a decarburization process, and a stainless steel refining process. It is not limited to these. In the present invention, one or more of these steelmaking dusts can be used.
Although the rate of steelmaking dust varies from steelworks to steelworks, the amount generated is proportional to the amount of crude steel produced, so it is available in large quantities. Moreover, since the value of steelmaking dust is equivalent to that of crude steel, it is very inexpensive at around tens of thousands of yen per ton. On the other hand, a commercially available catalyst costs several million yen per ton, and it is very advantageous in terms of cost to use steelmaking dust as the granular material (f).

Steelmaking dust generally has a particle size distribution with a particle size lower limit of about 0.1 μm and an upper limit of about 200 μm, a median diameter (d50) of about 5 to 30 μm, and a specific surface area of 10 to 20 m ² / g. A coarse particle having a particle size distribution in which the lower limit of particle size is about 1 μm, the upper limit is about 2000 μm, the median diameter (d50) is about 30 to 200 μm, and the specific surface area is 1 m ² / g or less. There is grain dust. In general, exhaust gas discharged mainly from converters in the steelmaking process is collected in a wet form, but the amount that can be separated from water without adding a flocculant is coarse dust, and the addition of a flocculant is necessary for separation. Minutes are fine dust.

  In this method, either fine dust or coarse dust may be used. However, when fine dust and coarse dust are compared, fine dust has a higher specific surface area than coarse dust and therefore has higher catalytic activity, while the stability in fluidized state is better than coarse dust than fine dust. Is excellent. Further, since the iron content on the surface of the steelmaking dust particles is oxidized, the proportion of the oxidized iron content is increased in the fine dust having a larger specific surface area. For this reason, since the true density is larger in the coarse dust than in the fine dust, the blowing power of the mixed gas (g) which is a fluidized gas is larger in the case where the coarse dust is used. From the above points, by mixing and using fine dust and coarse dust, it is possible to form a fluidized bed in which high catalytic activity, stability in a fluidized state, and suppression of blowing power are ensured in a well-balanced manner. .

  A suitable mixing ratio of the fine dust and the coarse dust is not limited because it depends on the ratio [Lf / D] of the fluidized bed height Lf and the inner diameter D of the reactor, but generally, the fine dust and the coarse dust are mixed. The ratio [fine dust: coarse dust] (mass ratio) is suitably about 1:10 to 1: 5 when Lf / D is about 0.1 to 0.5, and Lf / D is 0.00. When the ratio is more than 5 to 2, about 1: 5 to 1: 1 is appropriate, and when Lf / D is more than 2 to about 10, about 1: 1 to 5: 1 is appropriate.

Moreover, as a granular material (f), what carried out the classification process to about several dozen-several hundred micrometers after drying a mill scale etc. besides the steelmaking dust mentioned above can also be used. Such a classified product such as mill scale contains a large amount of iron as well as steelmaking dust, so it can be used alone as a granular material (f), but both catalytic activity and flow characteristics are better than steelmaking dust. Since it is low, it is preferable to use it mixed with steelmaking dust.
In addition, reduced iron powder produced by reducing the mill scale and atomized iron powder produced from molten steel by the water atomization method can be used alone as a powder (f). Since it is large, it is better to mix it with steelmaking dust and use it with good fluidity.
Therefore, the powder (f) is at least partly made of steelmaking dust, preferably mainly made of steelmaking dust (that is, containing 50% by mass or more of steelmaking dust), more preferably steelmaking dust. It is desirable to consist of.

The fluid medium is mainly composed of the powder (f) (that is, containing 50% by mass or more of the powder (f)), but other powders may be added. For example, by mixing one or more inorganic powders such as alumina powder and silica sand, the fluidity can be further improved and the increase in the blowing power of the mixed gas (g) can be suppressed. When the inorganic powder is mixed, the mixing ratio is set to less than 50% by mass so as not to cause a significant decrease in the catalytic activity of the granular material (f).
As shown in FIG. 6, a mixed gas (g) that is a fluidized gas of a fluidized medium is supplied from the lower part of the fluidized bed reactor and blown upward from the gas dispersion plate 201 to form a fluidized bed 23. The flow rate of the mixed gas (g) blown out from the gas dispersion plate 201 is only required to maintain a good dispersion state, and is usually about 0.05 to 2 m / sec. If it is less than 0.05 m / sec, the fluidity decreases. On the other hand, if the flow rate exceeds 2 m / sec, there is no problem in fluidity, but the flow rate of the gas (g _p ) discharged from the fluidized bed reactor 20 increases, and the amount of scattering of the fluidized medium increases, resulting in cyclones and the like. Not only the load of the dust collector becomes excessive, but also the particle size of the solid organic material when the solid organic material is supplied from the upper part of the reactor needs to be increased as described later, so that the reaction efficiency is lowered.

  As a method for supplying the organic substance into the fluidized bed reactor 20, a liquid organic substance such as oil-containing sludge or waste oil may be sprayed by a spray nozzle or the like, and the supply position may be the upper part of the fluidized bed reactor 20 or gas dispersion. Any position such as the upper part of the plate 201 may be used. On the other hand, in the case of a solid organic material such as plastic or biomass, it is generally supplied from the upper part of the fluidized bed reactor 20, but a part of the mixed gas (g) is branched and mixed gas (g). It is also possible to supply the upper part of the gas dispersion plate 201 by pneumatic transportation. In addition, when supplying a solid organic substance from the upper part of the fluidized bed reactor 20, it is easier to drop by gravity rather than supplying by pneumatic transportation. However, in that case, it is preferable to mold the supplied solid organic material so that the particle size and density do not scatter, and to select a particle size that does not reduce the reaction efficiency.

In this method, plastics and other organic substances are reduced in molecular weight, and the number of molecules of gas flowing in the reactor increases by about twice, so the flow rate of the product gas in the reactor is twice that of the mixed gas (g). It must be noted that For example, if the flow rate of the mixed gas (g) is 0.05 m / sec, the flow rate of the product gas is about 0.1 m / sec. Therefore, the true density of the solid organic substance is preferably 1 g / cm ^3. The particle size is about 2 to 6 mm. Moreover, if the flow rate of the mixed gas (g) is 2 m / sec, the flow rate of the product gas is about 4 m / sec. Therefore, when the true density of the organic substance is 1 g / cm ³ , the preferred particle size is 15 to It is about 20 mm.

Hydrogen produced by the method of the present invention (including the case of a hydrogen-rich mixed gas; the same applies hereinafter) can be applied to any application, and can be used as, for example, high-purity hydrogen for fuel cells.
Further, as a method of operating a steel mill, hydrogen produced by the method of the present invention can be used as one or more of a source gas, a reducing agent, and a fuel in the steel mill. Specifically, it used as (A) used as a reducing agent for iron ore by blowing into the blast furnace, (b) the raw material gas for the methanation of CO ₂ and CO discharged like a blast furnace, (c ) It can be used as a fuel for equipment in steelworks.

That is, the hydrogen produced by the production method of the present invention is, for example, (1) a method of operating a blast furnace that is blown into the blast furnace as a reducing agent, and (2) any one of a raw material gas, a reducing agent, and a fuel in the steelworks. It can be used for the operation method of the steelworks used as above. In that case, the hydrogen-rich mixed gas obtained by steam reforming or the subsequent shift reaction may be used as it is, or hydrogen gas (high-purity hydrogen gas) separated from the mixed gas by a gas separator is used. May be.
When hydrogen produced by the method of the present invention is blown into a blast furnace or the like as a reducing agent, it is preferably used after removing CO ₂ or H ₂ O in order to increase the reduction efficiency. There are no particular limitations on the method for removing impurities such as CO ₂ , H ₂ O, and trace amounts of hydrocarbons.

  In addition, since the liquid product produced | generated by the modification | reformation reaction of an organic substance consists of C5-C24 hydrocarbon, naphtha (C5-C8), kerosene (C9-C12), and light oil (C13-C24) It is a mixture and is a high quality light oil that contains almost no heavy oil equivalent (C25 or higher). This liquid product may be used separately as naphtha, kerosene, or light oil by distillation separation, but as a mixture, it can be used as a reducing agent instead of heavy oil in blast furnaces and fuels in factories with metallurgical furnaces such as ironworks. Can be used. Since the content of naphtha (C5 to C8) is high, the naphtha is separated by distillation and used as a raw material for chemical industry. Only the distillation residue (mixture of kerosene and light oil) after separation of naphtha is replaced with heavy oil at the steelworks It may be used as a reducing agent.

In addition, from the point mentioned above, if the mixed gas of the composition equivalent to the mixed gas (g) obtained by this invention is used, an organic substance can be decomposed | disassembled efficiently and a molecular weight can be reduced. In particular, water vapor concentration: 20-70 vol%, hydrogen concentration: 10-40 vol%, carbon dioxide concentration: 40 vol% or less, more preferably water vapor concentration: 25-65 vol%, hydrogen concentration: 15-35 vol%, carbon dioxide concentration: 35 vol By using a mixed gas that is less than or equal to%, the decomposition rate of the organic substance can be sufficiently increased, and the LHV of the gas product can be increased. In addition, it does not prevent that other gas components (for example, nitrogen etc.) are contained in this mixed gas.
The reason for limiting the gas composition is the same as the reason for limitation in the method of the present invention described above. In order to obtain a mixed gas having such a composition other than the method of the present invention, for example, one or more of water vapor, hydrogen, and carbon dioxide gas is added to the base gas.
The conditions for modifying (decreasing the molecular weight) of the organic substance by the mixed gas are the same as the conditions for modifying (decreasing the molecular weight) in the method of the present invention described above.

Therefore, the gist of the method is as described in [1] to [17] below, and examples of the present invention described later are also examples of the following method.
[1] The organic substance is modified to lower the molecular weight by bringing a mixed gas having a water vapor concentration of 20 to 70 vol%, a hydrogen concentration of 10 to 40 vol%, and a carbon dioxide concentration of 40 vol% or less into contact with the organic substance. A method for producing hydrogen, characterized in that hydrogen is produced by causing a reaction and steam reforming a product produced by the reforming reaction.
[2] A method for producing hydrogen according to the method of [1], wherein the product produced by the reforming reaction of the organic substance is subjected to steam reforming and then subjected to a shift reaction to generate hydrogen. .
[3] A method for producing hydrogen according to the method of [2], wherein after the gas generated by the steam reforming is cooled, the shift reaction is performed by adding steam or / and water.
[4] A method for producing hydrogen according to the method of [3], wherein a gas generated by steam reforming is subjected to a shift reaction at 200 to 300 ° C.

[5] The method according to any one of [1] to [4] above, wherein a gas product is separated from a product generated by a reforming reaction of an organic substance, and the gas product is steam reformed. To produce hydrogen.
[6] The method according to any one of [1] to [4] above, wherein a liquid product is separated from a product generated by a reforming reaction of an organic substance, and the liquid product is steam-reformed. To produce hydrogen.
[7] In any one of the above methods [1] to [6], the organic material reforming reaction and the steam reforming of the product generated by the reforming reaction are performed in separate reactors, and the organic material A method for producing hydrogen, wherein steam reforming is performed by adding steam to a product produced by the reforming reaction.
[8] In any of the methods [1] to [4] above, using a mixed gas (g) containing or added with water vapor necessary for steam reforming, reforming reaction of an organic substance, A method for producing hydrogen, characterized in that steam reforming of a product generated by this reforming reaction is performed in one reactor.

[9] In any of the methods [1] to [8] above, the mixed gas (g) is brought into contact with the organic substance in the fluidized bed, thereby causing a reaction for modifying the organic substance to reduce the molecular weight. A method for producing hydrogen, comprising:
[10] In the method of [9] above, at least a powder (f) having a true density of 4 to 8 g / cm ³ and containing at least one selected from Fe, Ni, and Cr is at least a fluid medium. A method for producing hydrogen, comprising using a fluidized bed as a part of
[11] A method for producing hydrogen according to the method of [10], wherein at least a part of the granular material (f) is iron-containing dust generated in a steelmaking process.
[12] The method for producing hydrogen according to the above [11], wherein the granular material (f) is iron-containing dust generated in a steelmaking process.
[13] In any one of the above methods [10] to [12], the gas (g _p ) discharged from the fluidized bed is passed through a dust collector, and the fluid medium contained in the gas (g _p ) is collected. A method for producing hydrogen, wherein the collected fluid medium is circulated in a fluidized bed.

[14] The method for producing hydrogen according to any one of the above [1] to [13], wherein hydrogen is separated from a gas obtained by steam reforming or a subsequent shift reaction to obtain hydrogen gas .
[15] In any one of the above methods [1] to [14], heat is recovered from the gas generated by the steam reforming and / or the gas generated by the shift reaction after the steam reforming, and the recovered heat is A method for producing hydrogen, characterized by being used as a heat source for producing steam for steam reforming and / or steam for shift reaction.
[16] In any one of the above methods [1] to [15], by reforming off-gas and / or organic substances after separating hydrogen from the gas obtained by steam reforming or the subsequent shift reaction Part of the produced gas product is used as a heat source fuel for a steam reforming reactor.
[17] The hydrogen according to any one of the above [1] to [16], wherein the organic substance to be modified is one or more selected from plastic, oil-containing sludge, waste oil, and biomass. Manufacturing method.

[Example 1]
・ Invention Example 1
A converter gas is used as an exhaust gas generated from a metallurgical furnace containing carbon monoxide, and the converter gas is converted into a mixed gas mainly composed of H ₂ , CO ₂ , and H ₂ O by a shift reaction. Steam was added to the water (see equation (2)), and hydrogen was produced in a single reactor using a low molecular weight reaction and steam reforming reaction of polyethylene as a model material for waste plastic. In the examples of the present invention, the shift reaction for the purpose of producing hydrogen from residual CO after steam reforming was omitted because there was no technical problem.

  A branch pipe is provided in the gas discharge pipe of the gas holder for temporarily storing the converter gas, and a part of the converter gas can be extracted through the branch pipe. Downstream of this branch pipe are a flow control valve, steam mixer, preheater (for converter gas and steam mixed gas), shift reactor (cylindrical vertical type), reforming reactor (external heating type rotary kiln). Also, a screw conveyor type waste plastic quantitative charging device was installed on the inlet side of the reforming reactor. The portion downstream of the sampling port for analysis of the reforming reaction product was a steam reforming portion for hydrogen production. A shift reactor for converting residual CO after steam reforming to hydrogen was installed on the downstream side of the furnace in which the low molecular weight reaction and the steam reforming reaction were integrated. Depending on the experiment, the steam reforming furnace and the shift reactor for hydrogen conversion of residual CO can be bypassed.

The average composition of the converter gas in the gas _{holder, H 2: 12vol%, CO} : 54vol%, CO 2: 17vol%, H 2 O: 1vol%, N 2: was 16 vol%. The converter gas 74 nm ³ / h, a steam pressure 10 kg / cm ² G and 100 Nm ³ / h supplied as steam against a steam mixer, after raising the temperature to 320 ° C. in the preheater, the shift reactor (Fe- (Cr-based high temperature shift catalyst filling). Due to the shift reaction in the shift reactor, gas having a gas composition of H ₂ : 26 vol%, CO: ₂ vol%, CO ₂ : 28 vol%, H ₂ O: 37 vol%, N ₂ : 7 vol% (shift reaction product gas) Obtained. This shift reaction product gas had a flow rate of 172 Nm ³ / h (170 kg / h in mass flow rate) and a reactor outlet gas temperature of 430 ° C.

The externally heated rotary kiln, which is a reforming reactor, is preheated to 500 ° C. in advance, and the reforming reactor is supplied with the above-mentioned total amount of shift reaction product gas and steam at a pressure of 20 kg / cm ² G as steam for steam reforming. 1900 Nm ³ / h and polyethylene crushed into a granular material as a model material of waste plastic at 880 kg / h, the temperature is raised to 900 ° C. which is the planned reaction temperature, reaches 900 ° C., and the reaction is stabilized. For another 2 hours, the reforming reaction for reducing the molecular weight of the waste plastic and the steam reforming reaction of the product produced by this reforming reaction were continued. As a result, 5230 Nm ³ / h of steam reformed product gas with H ₂ : 61 vol%, CO: 27 vol%, CO ₂ : 3 vol%, H ₂ O: 9 vol%, and N ₂ : <1 vol% was produced. Although not quantitative, solid residues such as unreacted polyethylene were not observed.

Considering the shift reaction, one molecule of CO corresponds to one molecule of H ₂ . On the other hand, since waste plastic is carbon-free and steam can be produced by waste heat recovery, only H ₂ and CO in the converter gas are regarded as the hydrogen source in the raw material. Since the total flow rate of H ₂ and CO in the converter gas is 49 Nm ³ / h and the amount of generated hydrogen is 3190 Nm ³ / h, 65 times as much H _{2 as} the hydrogen source in the converter gas was produced. It corresponds to that.
In the examples of the present invention, hydrogen production by shift reaction of CO remaining by steam reforming was omitted. If the shift reaction is performed at 250 ° C., it is calculated from the equilibrium calculation that hydrogen of 1050 Nm ³ / h can be produced. Therefore, the total hydrogen production including the shift reaction of residual CO reaches 86 times the hydrogen source in the converter gas.

・ Invention Example 2
The blast furnace gas was used as the exhaust gas generated from the metallurgical furnace containing carbon monoxide, and after the low molecular weight reaction of polyethylene was performed, the entire amount of the low molecular weight product was introduced into the steam reforming furnace. Furthermore, in order to produce hydrogen from CO remaining after steam reforming, the entire amount of the steam reforming product was introduced into the shift reactor. Since the composition of the blast furnace gas after desulfurization / drying treatment was H ₂ : 3 vol%, CO: 23 vol%, CO ₂ : 21 vol%, N ₂ : 53 vol%, N ₂ separation was performed by the PSA method described below. And concentrated the CO.

The above-mentioned blast furnace gas was supplied at 136 Nm ³ / h at normal pressure to an adsorption tower packed with 400 kg of Cu ⁺ supported activated carbon as an adsorbent. Desorption was performed at 7 kPa (absolute pressure), and the composition of the desorption gas was H ₂ : <1 vol%, CO: 47 vol%, CO ₂ : 37 vol%, N ₂ : 16 vol%, and the flow rate was 58 Nm ³ / h. . The CO and steam 73 nm ³ / h a pressure 10 kg / cm ² G was supplied to the steam mixer as blast furnace gas 58 nm ³ / h and steam was concentrated and subjected to a shift reaction in the same manner as in Invention Example 1. As a result, a gas (shift reaction product gas) having a gas composition of H ₂ : 19 vol%, CO: ₂ vol%, CO ₂ : 35 vol%, H ₂ O: 37 vol%, and N ₂ : 7 vol% was obtained. This shift reaction product gas had a flow rate of 130 Nm ³ / h (146 kg / h in mass flow rate) and a reactor outlet gas temperature of 430 ° C. Using this shift reaction product gas, polyethylene was subjected to a molecular reduction reaction at a reaction temperature of 600 ° C. As a result of the reaction, the gas product yield was 280 kg / h, the liquid product yield was 590 kg / h, and the polyethylene degradation rate was 85%.

Next, steam reforming is performed at a temperature of 1000 ° C. by supplying the total amount of the low molecular weight reaction product including unreacted polyethylene and steam 1490 Nm ³ / h at a pressure of 20 kg / cm ² G to the steam reforming furnace as steam. It was. As a result, 4470 Nm ³ / h of steam reforming product gas having H ₂ : 64 vol%, CO: 31 vol%, CO ₂ : 1 vol%, H ₂ O: 3 vol%, and N ₂ : 1 vol% was produced. Further, the temperature of the steam reforming product gas was cooled to 250 ° C., mixed with steam 1300 Nm ³ / h at a pressure of 20 kg / cm ² G, and supplied to the shift reactor. As a result of the shift reaction at a reaction temperature of 250 ° C., 5770 Nm of shift reaction product gas with H ₂ : 70 vol%, CO: 4 vol%, CO ₂ : 21 vol%, H ₂ O: 5 vol%, N ₂ : <1 vol%. ³ / h was produced. Although not quantitative, it seems that solid substances such as unreacted polyethylene were also modified in the steam reforming furnace.
In the same manner as in Invention Example 1, it was calculated how many times as much hydrogen as the hydrogen source in the raw material gas could be produced. The total flow rate of H ₂ and CO in the blast furnace gas is 35 Nm ³ / h, and the total amount of hydrogen produced (total amount of hydrogen after the shift reaction of residual CO) is 4040 Nm ³ / h. This is equivalent to producing 115 times more H ₂ .

-Invention Example 3
The present invention example was not polyethylene, but a reforming reaction (reducing the molecular weight of the plastic, steam reforming of the lower molecular weight reaction product, A shift reaction of the residual CO was performed.
As a result of solvent waste extraction and analysis using an infrared spectrophotometer, the used plastic was 74% by mass of polyolefin such as PP, 16% by mass of polyester such as PET, 3% by mass of ash, and 7% by mass of others. . In addition to these, impurities such as metals were observed, but they were removed and used for the experiment. As a result, in the molecular weight reduction reaction, the amount of product was reduced by about 10%, resulting in a gas product production of 250 kg / h and a liquid product production of 550 kg / h. Results The product was steam _{reforming, H 2: 63vol%, CO} : 30vol%, CO 2: 1vol%, H 2 O: 4vol%, N 2: 3vol% ( flow rate: 4020Nm ³ / h) of gas As a result of further shift reaction of residual CO of this steam reforming product gas, H ₂ : 68 vol%, CO: 4 vol%, CO ₂ : 21 vol%, H ₂ O: 5 vol%, N ₂ : ₂ vol % (Flow rate: 5300 Nm ³ / h) of gas was produced.

In the same manner as in Invention Example 1, it was calculated how many times as much hydrogen as the hydrogen source in the raw material gas could be produced. Since the total flow rate of H ₂ and CO in the blast furnace gas is 35 Nm ³ / h and the total amount of hydrogen generated (total hydrogen amount after the shift reaction of residual CO) is 3600 Nm ³ / h, the hydrogen source of the blast furnace gas 103 times of H ₂ is equivalent to that produced.
In actual waste plastic, the efficiency decreased by about 10% compared to polyethylene. However, since 3% by mass of ash that is not involved in the reaction is present in the waste plastic, the efficiency reduction of 3% is obvious. On the other hand, the relatively highly reactive polyolefin is only 74% by mass, and if only the polyolefin is reacted, the efficiency should be reduced by 26%. Since the actual efficiency drop is about 10%, it is considered that polyester such as PET also reacted and changed to hydrogen.

[Example 2]
Invention example 4
A branch pipe is provided in the gas discharge pipe of the gas holder for temporarily storing the converter gas, and a part of the converter gas can be extracted through the branch pipe. Downstream of this branch pipe is a flow control valve, steam mixer, preheater (for converter gas and steam mixed gas), shift reactor (cylindrical vertical type), reforming reactor (externally heated rotary kiln), A gas cooler for cooling the reformed reaction product gas provided with a liquid fuel collector was arranged in this order. On the inlet side of the reforming reactor, a screw conveyor type waste plastic quantitative charging device was installed. A sampling port and a flow meter were installed in the outlet piping of the shift reactor and the outlet piping of the gas after cooling of the gas cooler.

The average composition of the converter gas in the gas _{holder, H 2: 12vol%, CO} : 54vol%, CO 2: 17vol%, H 2 O: 1vol%, N 2: was 16 vol%. The converter gas 74 nm ³ / h, a steam pressure 10 kg / cm ² G and 100 Nm ³ / h supplied as steam against a steam mixer, after raising the temperature to 320 ° C. in the preheater, the shift reactor (Fe- (Cr-based high temperature shift catalyst filling). Due to the shift reaction in the shift reactor, gas having a gas composition of H ₂ : 26 vol%, CO: ₂ vol%, CO ₂ : 28 vol%, H ₂ O: 37 vol%, N ₂ : 7 vol% (shift reaction product gas) Obtained. This shift reaction product gas had a flow rate of 172 Nm ³ / h (170 kg / h in mass flow rate) and a reactor outlet gas temperature of 430 ° C.

The externally heated rotary kiln, which is a reforming reactor, is preheated to 500 ° C. in advance, and 880 kg of polyethylene that has been crushed into granules as a model material of waste plastic is introduced into this reforming reactor while introducing a shift reaction product gas. / H, and the temperature was raised to 800 ° C., which is the planned reaction temperature. After reaching 800 ° C., the liquid product collected in the liquid product collector was discharged, and then the reforming reaction of the waste plastic was continued for 1 hour.
The amount and composition of the gas product are determined from the gas analysis results after cooling by the gas cooler, and the liquid product content is determined from the analysis results of the liquid product collected in the liquid product collector. Moreover, LHV was calculated | required about the gaseous product. The results are shown in Table 1.

Since the total amount of shift reaction product gas and polyethylene supplied as raw materials was 1050 kg / h, the production rate relative to the total amount of the feed materials was 36% for gas products and 62% for liquid products. Since it is difficult to directly measure the amount of unreacted polyethylene, the sum of gas product (380 kg / h) and liquid product (650 kg / h) relative to the total amount of shift reaction product gas and polyethylene (1050 kg / h) supplied. When the yield is defined as the polyethylene decomposition rate, in Example 4, the polyethylene decomposition rate is a sufficiently high value of 98%, and the production of hydrocarbons of C25 or higher is hardly observed. It is clear that the molecular weight was reduced. H ₂ O, CO ₂ and H ₂ are completely consumed by the reforming reaction of the organic substance, and it is considered that four reactions of steam reforming, carbon dioxide reforming, hydrogenation, and hydrocracking proceeded simultaneously. . The LHV of the produced gas product was 8.9 Mcal / Nm ³ and increased to 4.7 times that of the converter gas (1.9 Mcal / Nm ³ ).

Next, hydrogen was produced from the gas products shown in Table 1 as follows using the production facility shown in FIG. The gas product (380 kg / h) shown in Table 1 was pressurized to 0.25 MPa by the compressor 8 and then introduced into the steam reforming reactor 3, and steam was added to the steam reforming reactor 3 to 750. A steam reforming reaction was performed at 0 ° C. In addition, the addition amount of water vapor | steam was 2700 kg / h (14 times the stoichiometric water amount which carries out the steam reforming of the said gas product). After the gas obtained by this steam reforming was cooled to 230 ° C. by the heat exchanger 9, it was introduced into the shift reactor 5 and further steam was added to carry out a shift reaction. The addition amount of water vapor was 900 kg / h (three times the shift reaction stoichiometric amount of the gas). The hydrogen-rich gas obtained by this shift reaction was further cooled by the heat exchanger 10, the moisture was separated by the separator 11, and then the pressure was increased to 0.9 MPa by the compressor 12. Furthermore, after cooling with the cooler 13, high purity hydrogen (purity: 99.999% or more) was able to be produced at 4000 Nm ³ / h by separating hydrogen with a gas separator 14 (for example, PSA gas separator). . In addition, as shown by gas lines 15 and 16 in FIG. 5, a part of the gas product as a raw material and the off-gas of the gas separation device 14 were used as a heat source for the steam reforming reactor 3.

  By separating only the gaseous product from the reforming reaction product of waste plastic and using it as a raw material for hydrogen production, the generation of soot that would be a problem in reforming liquid products (light oil, etc.) was not observed. . In addition, there was no trouble such as blockage of the compressor and piping. In this example, polyethylene was used as a model of waste plastic, so residue and chlorine derived from waste plastic are not generated.However, if the target product is actual waste plastic and gas products are not separated, It is clear that troubles such as piping blockage, thinning, and corrosion occur.

-Invention Examples 5-13
In the same equipment as Invention Example 4, except that the steam flow rate supplied to the shift reactor was changed variously and the reforming reaction temperature of polyethylene was set at two levels of 800 ° C. and 500 ° C., the same as in Invention Example 4. Then, experiments were conducted on the shift reaction of converter gas and the reforming reaction of polyethylene using the shift reaction product gas. The results are shown in Table 2 and FIGS.

FIG. 7 shows the relationship between the water vapor concentration of the shift reaction product gas and the gasification rate and liquefaction rate in the reforming of polyethylene (reaction temperature: 800 ° C.). Here, the gasification rate is a ratio of the production amount (kg / h) of the gas product to the total amount (kg / h) of the supplied shift reaction product gas and polyethylene, and the definition of the gas product is shown in Table 1. It was hydrocarbons from H ₂ to C4 as shown in. Similarly, the liquefaction rate is a ratio of the production amount (kg / h) of the liquid product to the total amount (kg / h) of the supplied shift reaction product gas and polyethylene, and the definition of the liquid product is shown in Table 1. As shown, C5 to C24 hydrocarbons were used. FIG. 8 shows the relationship between the water vapor concentration of the shift reaction product gas and the LHV of the gas product and liquid product obtained by the modification of polyethylene (reaction temperature: 800 ° C.). Here, the LHV of the liquid product was expressed as LHV per volume in the standard state in terms of gas of the liquid product. FIG. 9 shows the relationship between the water vapor concentration of the shift reaction product gas and the polyethylene decomposition rate due to the modification of polyethylene. In particular, it shows that the polyethylene decomposition rate is equivalent at reaction temperatures of 500 ° C. and 800 ° C. It is a thing. FIG. 10 shows the relationship between the carbon dioxide concentration of the shift reaction product gas and the hydrogen concentration of the gas product obtained by the reforming of polyethylene (reaction temperature: 800 ° C.). FIG. 11 shows the relationship between the hydrogen concentration of the shift reaction product gas and the carbon dioxide concentration of the gas product obtained by the reforming of polyethylene (reaction temperature: 500 ° C.).
Hydrogen was produced from the gas product and liquid product shown in Table 2 under the same conditions as in Invention Example 4. As a result of adjusting the amount of water vapor added according to the composition of the gas product and the liquid product, there was no trouble such as soot formation or compressor / piping blockage, and hydrogen could be produced without any problems.

Invention Example 14
Using the equipment shown in FIG. 4, the shift reaction of the exhaust gas generated from the metallurgical furnace and the reforming of the organic substance were performed. This equipment is provided with a vertical reforming reactor 2 (internal volume: about 3 m ³ ) having a gas dispersion plate 200 at the bottom. Was filled with 880 kg of polyethylene a, and a metal net b (10 mesh) was placed on the top, and further Ni catalyst c (Ni loading: 10% by mass, support: α-Al ₂ O ₃ ) was 800 kg on the top. Filled. The shift reaction product gas generated in the shift reactor 1 is introduced into the bottom of the reforming reactor 2, and is supplied into the reactor through the gas dispersion plate 200, and rises in the reactor. The reformed product is discharged from the upper part of the reforming reactor 2 and separated into a gas product and a liquid product by the liquid product collector 6. The separated gas product is cooled by the gas cooler 7. The equipment configuration from the gas holder for temporarily storing the converter gas to the shift reactor 1 was the same as that of Invention Example 4.

Except for using the above equipment and setting the planned reaction temperature in the reforming reactor 2 to 750 ° C., the same conditions as in Invention Example 4 (conditions for obtaining the converter gas composition, shift reaction product gas, shift The reaction reaction gas composition, temperature, flow rate, etc.) were used to conduct experiments on the reforming of polyethylene.
The production amount and composition of the gas product and the liquid product were determined in the same manner as in Invention Example 4. The results are shown in Table 3. The reaction results are almost the same as those of Invention Example 4, and the reaction temperature in the reforming reactor 2 is 750 ° C., which is 50 ° C. lower than that of Invention Example 4, which is considered to be due to the effect of catalyst addition.
Hydrogen was produced from the gaseous product under the same conditions as in Invention Example 4. Similar to Invention Example 4, there were no troubles such as soot formation or compressor / piping blockage, and hydrogen could be produced without any problems.

-Invention Example 15
Blast furnace gas was used as an exhaust gas generated from a metallurgical furnace containing carbon monoxide. The composition of the blast furnace gas after desulfurization / drying treatment was H ₂ : 3 vol%, CO: 23 vol%, CO ₂ : 21 vol%, N ₂ : 53 vol%, so that nitrogen separation was performed by the PSA method described below, Increased concentration of carbon monoxide.
In nitrogen separation by the PSA method, the above blast furnace gas was supplied at 136 Nm ³ / h at normal pressure to an adsorption tower packed with 400 kg of Cu ⁺ supported activated carbon as an adsorbent. Desorption is performed at 7 kPa (absolute pressure), and the composition of the desorption gas (= blast furnace gas enriched with carbon monoxide) is H ₂ : <1 vol%, CO: 47 vol%, CO ₂ : 37 vol%, N ₂ : 16 vol%, The flow rate was 58 Nm ³ / h. The carbon monoxide and steam 73 nm ³ / h a pressure 10 kg / cm ² G was supplied to the steam mixer as blast furnace gas 58 nm ³ / h and steam were concentrated and subjected to a shift reaction in the same manner as in Invention Example 4. As a result, a gas (shift reaction product gas) having a gas composition of H ₂ : 19 vol%, CO: ₂ vol%, CO ₂ : 35 vol%, H ₂ O: 37 vol%, and N ₂ : 7 vol% was obtained.

This shift reaction product gas had a flow rate of 130 Nm ³ / h (146 kg / h in mass flow rate) and a reactor outlet gas temperature of 430 ° C. A polyethylene reforming reaction was carried out in the same manner as in Invention Example 4 except that this shift reaction product gas was used and the reforming reaction temperature was set to 600 ° C. The reaction results are 280 kg / h of gas product, 590 kg / h of liquid product, 85% polyethylene decomposition rate, LHV 7.3 Mcal / Nm ³ of gas product, and blast furnace gas enriched with carbon monoxide It was confirmed that the reaction proceeded with high efficiency. Moreover, since the LHV of the blast furnace gas is 770 kcal / Nm ³ , it was possible to obtain a gas with 9 times or more combustion heat.
Hydrogen was produced from the gaseous product under the same conditions as in Invention Example 4. Similar to Invention Example 4, there were no troubles such as soot formation or compressor / piping blockage, and hydrogen could be produced without any problems.

Comparative example 1
In order to examine the reforming reaction efficiency of polyethylene with a gas having a low water vapor and hydrogen concentration, H ₂ : 1 vol%, CO: 61 vol%, CO ₂ : 19 vol%, H ₂ O: 1 vol%, N ₂ : 18 vol% A standard gas of composition was made, and a polyethylene reforming reaction experiment was conducted with this gas. As a result, even at a temperature of 800 ° C., the polyethylene degradation rate was only 16%, the gasification rate was 10%, and the liquefaction rate was only 5%.

[Example 3]
Invention Example 16
A branch pipe for a laboratory test is provided in the gas discharge pipe of the gas holder for temporarily storing the converter gas, and a small flow rate of the converter gas can be extracted through the branch pipe. Downstream of this branch pipe are a flow control valve, a steam mixer, a preheater (for mixed gas of converter gas and steam), a fixed bed shift reactor (inner diameter 30 mm), and an externally heated fluidized bed reactor (inner diameter 44 mm). ) Were arranged in this order. Piping is connected so that the total amount of shift reaction product gas can be supplied from the bottom of the fluidized bed reactor, and a circle feeder type quantitative charging device is provided so that waste plastic can be dropped into the reactor from the top of the fluidized bed reactor. Was installed. From the upper part of the fluidized bed reactor, a product sampling port was connected via a cyclone as a first stage dust collector, a gas filter as a second stage dust collector, and a gas cooler. Since the cyclone dipleg is not inserted into the fluidized bed reactor, the fluid medium (catalyst) is not circulated in this embodiment.

The average composition of the converter gas in the gas _{holder, H 2: 12vol%, CO} : 54vol%, CO 2: 17vol%, H 2 O: 1vol%, N 2: was 16 vol%. The steam mixer was supplied with 74 NL / h of the converter gas and 100 NL / h of steam at a pressure of 10 kg / cm ² G as steam, and the temperature was raised to 320 ° C. with a preheater, and then the shift reactor (Fe-Cr system) High temperature shift catalyst filling). Due to the shift reaction in the shift reactor, gas having a gas composition of H ₂ : 26 vol%, CO: ₂ vol%, CO ₂ : 28 vol%, H ₂ O: 37 vol%, N ₂ : 7 vol% (shift reaction product gas) Obtained. This shift reaction product gas had a flow rate of 172 NL / h (170 g / h in mass flow rate) and a reactor outlet gas temperature of 430 ° C.
A gas dispersion plate is installed in the lower part of the externally heated fluidized bed reactor, which is a reforming reactor for reducing the molecular weight of organic substances, and decarburization blown as a fluidized medium (catalyst) above the gas dispersion plate. Converter dust coarse particles generated in (T-Fe: 80% by mass, average particle size: 80 μm, true density: 5.9 g / cm ³ , bulk density 2.9 g / cm ³ , Al ₂ O ₃ content 0. After charging 1 kg of 38 mass%), nitrogen gas was supplied at 50 NL / h to fluidize the converter dust. The fluidized bed height was about 280 mm (Lf / D = 6.4).

Next, after heating the fluidized bed reactor at a set temperature of 800 ° C., the fluidizing gas was switched from nitrogen to the shift reaction product gas (flow rate: 172 NL / h, flow rate at 800 ° C .: 0.12 m / sec). Next, a model waste plastic obtained by mixing 3.3% by mass of Al ₂ O ₃ (ash model material) with polyethylene into a particle size of 4 mm and a bulk density of 0.4 g / cm ³ is 910 g / h (880 g as polyethylene content) / H, Al ₂ O ₃ minutes at 30 g / h). Analysis of the gas after cooling by the gas _{cooler, CO: 63vol%, N 2} : 5vol%, CH 4: 6vol%, C 2 H 6: 3vol%, C 3 H 8: 7.5vol%, C 4 A gas having a composition of H ₁₀ : 15.5 vol% was generated at 260 NL / h. Since this is 380 g / h in terms of mass flow rate, the gasification rate was 37% by mass.

A vertical steam reforming reactor is installed downstream of the fluidized bed reactor for reducing the molecular weight of the organic substance, and the total amount of gas products (260 NL / h) and steam at a pressure of 10 kg / cm ² G were supplied as steam for steam reforming at 400 g / h (twice the stoichiometric amount of steam reforming) to perform a steam reforming reaction. The reactor outlet temperature was maintained at 700 ° C. by a heater attached outside the reactor. As a result, 1010 NL / h of a gas having a composition of H ₂ : 56 vol%, CO: 39 vol%, CO ₂ : 3 vol%, and N ₂ : ₂ vol% on a dry state basis was generated. Therefore, H ₂ was generated at 570 NL / h by the steam reforming reaction. In the present invention example, the shift reaction after the steam reforming reaction (shift reaction for producing H ₂ ) is omitted, but 390 NL / h of H ₂ is generated by the shift reaction, so the amount of H _{2 that} can be produced is Calculated as 960 NL / h.

In addition, although not quantitative, solid residues such as unreacted polyethylene were not observed in the molecular weight reduction reaction of polyethylene in the fluidized bed reactor. Moreover, there were no troubles such as fusion and blockage of polyethylene during the low molecular weight reaction. After the experiment was completed, the fluidized bed reactor was disassembled and the inside was observed, but formation of carbide was not observed, and it was confirmed that stable fluidization reaction could be performed by the fluidized bed. About 20 g of solid was recovered from the cyclone dipleg at the end of the experiment. When the recovered solid was analyzed, the Al ₂ O ₃ content was 0.42% by mass (0.084 g as the amount of Al ₂ O ₃ ). On the other hand, the solid collected by the gas filter which is a 2nd stage dust collector was about 26g. When the collected solid was analyzed, the Al ₂ O ₃ content was 99.6% by mass (25.9 g as the amount of Al ₂ O ₃ ), and the Fe content was below the detection limit. Considering experimental errors, it is considered that Al ₂ O ₃ which is a model ash and fluid medium (coarse dust) are almost completely separated.

Invention Example 17
A polyethylene low molecular weight reaction product supplied to a steam reforming reactor installed downstream of a fluidized bed reactor for reducing the molecular weight of an organic substance is a liquid product, and steam for steam reforming is 2100 g / h (steam reforming amount). A steam reforming reaction was carried out in the same manner as in Invention Example 16 except that the amount was twice the stoichiometric amount. The composition of the supplied liquid product was a hydrocarbon mixture of 62 mol% C5 to C8 hydrocarbons and 37 mol% C9 to C24 hydrocarbons, and the flow rate was 650 g / h. As a result of the steam reforming reaction, the production amount of H ₂ was 2500 NL / h.

・ Reference Example 1
Invention Example 16 except that blast furnace dust (T-Fe: 45 mass%, Al ₂ O ₃ content: 2 mass%, true density: 3 g / cm ³ , average particle size: 400 μm) was used as a fluid medium (catalyst) Similarly, a molecular weight reduction reaction test of Al ₂ O ₃ -containing polyethylene was performed.
As a result of the low molecular weight reaction test, there was no problem with the fluidized state, polyethylene fusion and clogging as in Example 16, but the solid density recovered from the cyclone was very small because the true density of the fluidized medium was low. Most solids (Al ₂ O ₃ which is blast furnace dust and model ash) were collected by a gas filter, and model ash and blast furnace dust could hardly be separated.

DESCRIPTION OF SYMBOLS 1 Shift reactor 2 Reformer reactor 3 Steam reformer reactor 4 Reformer reactor 5 Shift reactor 6 Liquid product collector 7 Gas cooler 8 Compressor 9 Heat exchanger 10 Heat exchanger 11 Separator 12 Compression Machine 13 Cooler 14 Gas separator 15, 16 Gas line 17 Steam supply line 20 Fluidized bed reactor 21 Discharge pipe 22a Primary dust collector 22b Secondary dust collector 23 Fluidized bed 24 Return pipe 200 Gas dispersion plate 201 Gas dispersion plate 202 Wind box Part a Plastic (or polyethylene)
b network c catalyst (or Ni catalyst)

Claims (22)

In producing hydrogen by reforming organic substances, it was generated by shift reaction by adding excess water vapor to exhaust gas (g ₀ ) containing carbon monoxide generated in metallurgical furnace to cause shift reaction. A mixed gas (g) containing hydrogen and carbon dioxide gas and water vapor that has not been consumed in the shift reaction is brought into contact with the organic substance to modify the organic substance to lower the molecular weight. A method for producing hydrogen, characterized in that hydrogen is produced by causing a reaction and steam reforming a product produced by the reforming reaction.   The method for producing hydrogen according to claim 1, wherein the mixed gas (g) has a water vapor concentration of 5 to 70 vol%.   The method for producing hydrogen according to claim 1 or 2, wherein the mixed gas (g) has a hydrogen concentration of 5 vol% or more and a carbon dioxide gas concentration of 5 vol% or more. The exhaust gas (g ₀ ) has a carbon monoxide concentration of 25 to 80 vol%, a carbon dioxide concentration of 10 to 25 vol%, a nitrogen concentration of 10 to 30 vol%, and a hydrogen concentration of 0 to 20 vol%. The manufacturing method of hydrogen in any one of 1-3.   The method for producing hydrogen according to any one of claims 1 to 4, wherein the product produced by the reforming reaction of the organic substance is subjected to steam reforming, and then hydrogen is generated by further performing a shift reaction. .   6. The method for producing hydrogen according to claim 5, wherein the shift reaction is performed by adding steam or / and water after cooling the gas generated by steam reforming.   The method for producing hydrogen according to any one of claims 1 to 6, wherein a gas product is separated from a product generated by a reforming reaction of an organic substance, and the gas product is steam reformed.   The method for producing hydrogen according to claim 1, wherein a liquid product is separated from a product generated by a reforming reaction of an organic substance, and the liquid product is steam reformed.   The reforming reaction of the organic substance and the steam reforming of the product generated by this reforming reaction are performed in separate reactors, and steam reforming is performed by adding steam to the product generated by the reforming reaction of the organic substance. The method for producing hydrogen according to any one of claims 1 to 8, wherein:   Using a mixed gas (g) containing or added with steam necessary for steam reforming, a reactor for reforming an organic substance and steam reforming a product generated by the reforming reaction The method for producing hydrogen according to any one of claims 1 to 6, wherein the method is carried out in the interior.   11. The hydrogen according to claim 1, wherein the mixed gas (g) has a water vapor concentration of 20 to 70 vol%, a hydrogen concentration of 10 to 40 vol%, and a carbon dioxide concentration of 10 to 40 vol%. Manufacturing method. The hydrogen composition according to any one of claims 1 to 11, wherein the gas composition of the mixed gas (g) is controlled by adjusting an excess ratio of water vapor added excessively to the exhaust gas (g ₀ ). Manufacturing method.   The mixed gas (g) is brought into contact with an organic substance in a fluidized bed, thereby causing a reaction for reforming the organic substance to lower its molecular weight. Production method. Use of a fluidized bed having a true density of 4 to 8 g / cm ³ and having a granular material (f) containing at least one selected from Fe, Ni, and Cr as at least a part of the fluidized medium. The method for producing hydrogen according to claim 13, characterized in that:   The method for producing hydrogen according to claim 14, wherein at least a part of the granular material (f) is iron-containing dust generated in a steelmaking process. The gas (g _p ) discharged from the fluidized bed is passed through a dust collector, the fluid medium contained in the gas (g _p ) is collected, and the collected fluid medium is circulated through the fluidized bed. The method for producing hydrogen according to claim 14 or 15. The exhaust gas (g ₀ ) is an exhaust gas having a carbon monoxide concentration increased by separating at least a part of nitrogen from exhaust gas containing carbon monoxide and nitrogen generated in a metallurgical furnace. The manufacturing method of hydrogen in any one of -16.   Heat recovery is performed from the gas generated by steam reforming and / or the gas generated by the shift reaction after steam reforming, and steam recovered for steam reforming and / or steam for shift reaction is generated from the recovered heat. It uses as a heat source for this, The manufacturing method of hydrogen in any one of Claims 1-17 characterized by the above-mentioned.   Part of the gas product produced by reforming the organic substance and off-gas after separating hydrogen from the gas obtained by steam reforming or the subsequent shift reaction is used as a heat source for the steam reforming reactor. It uses as a fuel, The manufacturing method of hydrogen in any one of Claims 1-18 characterized by the above-mentioned.   The method for producing hydrogen according to any one of claims 1 to 19, wherein the organic substance to be reformed is at least one selected from plastic, oil-containing sludge, waste oil, and biomass.   A method for operating a blast furnace, wherein hydrogen obtained by the method for producing hydrogen according to any one of claims 1 to 20 is blown into a blast furnace.   The operation of a steel mill, wherein the hydrogen obtained by the method for producing hydrogen according to any one of claims 1 to 20 is used as one or more of a raw material gas, a reducing agent, and a fuel in the steel mill. Method.

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